Sequences and their use for detection and characterization of STEC bacteria

ABSTRACT

This invention relates to a rapid method for detection and characterization of STEC bacteria based on the presence of nucleic acid sequences, in particular, to a PCR-based method for detection, and to oligonucleotide molecules and reagents and kits useful therefore. This method is preferably employed to detect STEC bacteria in a food or water sample, such as a beef enrichment. The present invention further relates to isolated polynucleotides, replication compositions, kits, and reagent tablets for carrying out the method of the present invention.

This application is a divisional of U.S. patent application Ser. No. 13/630,045, filed Sep. 28, 2012, now U.S. Pat. No. 8,802,371, which claims the benefit of U.S. Provisional Application 61/540,119 filed Sep. 28, 2011.

FIELD OF INVENTION

This invention relates to methods for detection and characterization of Shiga toxin producing Escherichia coli (STEC) bacteria based on the presence of nucleic acid sequences, preferably PCR-based methods for detection, and to oligonucleotide molecules and reagents and kits useful therefor.

BACKGROUND OF INVENTION

Escherichia coli (E. coli) is a gram-negative, rod-shaped bacterium. Although most strains of E. coli are benign and are found as normal intestinal flora of humans and other animals, some strains are pathogenic and can lead to disease. Different strains of pathogenic E. coli differ in their epidemiology, clinical course and potential for causing outbreaks of disease.

Shiga toxin producing Escherichia coli (STEC) is a type of enterohemorrhagic bacteria that can cause mild to severe intestinal disease, kidney problems, and even central nervous system effects. The pathogenicity of these bacterial strains is due, in large part, to their production of Shiga-like toxins Stx1 and Stx2. Additionally, production of the intimin adherence protein encoded by the eae gene has been linked to pathogenicity of bacteria, as has possession of certain surface antigens, including the O26, O111, O121, O45, O103, and O145 antigens.

One well-known serotype of STEC bacteria is E. coli serotype O157:H7, which has been associated with several food and water borne outbreaks. This bacterial serotype is regulated as an adulterant in ground beef by the U.S. Department of Agriculture (USDA) with a zero tolerance standard. Because of its tight regulation, numerous tests for E. coli O157:H7 exist in the market. However, numerous other STEC bacteria strains also can cause disease, making detection of other STEC bacterial serotypes, or STEC bacteria in general, important for improved food safety.

It is desirable, therefore, to have a test for the accurate detection and characterization of STEC bacteria in a sample.

SUMMARY OF INVENTION

One aspect of the present invention is a method for detecting the presence of STEC bacteria in a sample, said sample comprising nucleic acids, said method comprising:

-   -   (a) providing a reaction mixture comprising suitable primer         pairs for amplification of at least a portion of one or more of         the eae gene, the Stx1A gene, and the Stx2A gene;     -   (b) performing PCR amplification of said nucleic acids of said         sample using the reaction mixture of step (a); and     -   (c) detecting the amplification of step (b).

In certain examples, the invention relates to a method for detecting the presence of STEC bacteria in a sample, said sample comprising nucleic acids, said method comprising

-   -   (a) providing a reaction mixture comprising a first primer, a         second primer, and a probe for amplification and detection of at         least a portion of SEQ ID NO: 688 (eae); wherein each of said         first primer, second primer, and probe comprises a 5′ end and a         3′ end; wherein said first primer comprises at least 15         contiguous nucleotides of SEQ ID NO: 145 or a sequence         complementary thereto; and wherein said probe comprises at least         15 contiguous nucleotides of SEQ ID NO: 160 or a sequence         complementary thereto;     -   (b) performing PCR amplification of said nucleic acids of said         sample using the reaction mixture of step (a); and     -   (c) detecting the amplification of step (b).

In certain embodiments, the second primer comprises a nucleic acid sequence comprising at least 15 contiguous nucleotides of SEQ ID NO: 191 or a sequence complementary thereto. In further embodiments, the first primer comprises a sequence selected from the group consisting of SEQ ID NOs: 146-159, the second primer comprises a sequence selected from the group consisting of SEQ ID NOs: 192-205, and the probe comprises a sequence selected from the group consisting of SEQ ID NOs: 161-175. In additional embodiments, the 3′ end of the probe is directly or indirectly attached to the 5′ end of said the primer forming a primer-probe complex. In still further embodiments, the primer-probe complex can be detectably labeled. In additional embodiments, the reaction mixture further comprises a quencher oligonucleotide comprising at least 15 contiguous nucleotides of SEQ ID NO: 176. In some embodiments, the sample comprises a food sample or a water sample.

In other examples, the invention relates to a method for detecting the presence of STEC bacteria in a sample, said sample comprising nucleic acids, said method comprising

-   -   (a) providing a reaction mixture comprising a first primer, a         second primer, and a probe for amplification and detection of at         least a portion of SEQ ID NO: 686 (Stx1A); wherein each of said         first primer, second primer, and probe comprises a 5′ end and a         3′ end; and wherein said first primer and probe are selected         from the group consisting of:         -   (I) a first primer comprising at least 15 contiguous             nucleotides of SEQ ID NO: 1 or a sequence complementary             thereto and a probe comprising at least 15 contiguous             nucleotides of SEQ ID NO: 16 or a sequence complementary             thereto;         -   (II) a first primer comprising at least 15 contiguous             nucleotides of SEQ ID NO: 1 or a sequence complementary             thereto and a probe comprising at least 15 contiguous             nucleotides of SEQ ID NO: 49 or a sequence complementary             thereto; and         -   (III) a first primer comprising SEQ ID NO: 55 or a sequence             complementary thereto and probe comprising SEQ ID NO: 56 or             a sequence complementary thereto;     -   (b) performing PCR amplification of said nucleic acids of said         sample using the reaction mixture of step (a); and     -   (c) detecting the amplification of step (b).

In certain embodiments, the second primer comprises a nucleic acid sequence comprising at least 15 contiguous nucleotides of SEQ ID NO: 58 or comprising SEQ ID NO: 73. In other embodiments, the first primer comprises a sequence selected from the group consisting of SEQ ID NOs: 2-15, 48; the second primer comprises a sequence selected from the group consisting of SEQ ID NOs: 59-72; and the probe comprises a sequence selected from the group consisting of SEQ ID NOs: 17-30, 49-52. In further embodiments, the 3′ end of the probe is directly or indirectly attached to the 5′ end of the first primer forming a primer-probe complex. In still further embodiments, the primer-probe complex can be detectably labeled. In additional embodiments, the reaction mixture further comprises a quencher oligonucleotide comprising SEQ ID NO: 53, 54, or 57, or comprising at least 15 contiguous nucleotides of SEQ ID NO: 31. In some embodiments, the sample comprises a food sample or a water sample.

In still further examples, the present invention relates to a method for detecting the presence of STEC bacteria in a sample, said sample comprising nucleic acids, said method comprising

-   -   (a) providing a reaction mixture comprising a first primer, a         second primer, and a probe for amplification and detection of at         least a portion of SEQ ID NO: 687 (Stx2A); wherein each of said         first primer, second primer, and probe comprises a 5′ end and a         3′ end; and wherein said first primer and probe are selected         from the group consisting of:         -   (I) a first primer comprising at least 15 contiguous             nucleotides of SEQ ID NO: 74 or a sequence complementary             thereto and a probe comprising at least 15 contiguous             nucleotides of SEQ ID NO: 89 or a sequence complementary             thereto;         -   (II) a first primer comprising SEQ ID NO: 120 or a sequence             complementary thereto and a probe comprising SEQ ID NO: 121             or 122 or a sequence complementary thereto; and         -   (III) a first primer comprising SEQ ID NO: 125 or a sequence             complementary thereto and probe comprising SEQ ID NO: 126 or             a sequence complementary thereto;     -   (b) performing PCR amplification of said nucleic acids of said         sample using the reaction mixture of step (a); and     -   (c) detecting the amplification of step (b).

In certain embodiments, the second primer comprises a nucleic acid sequence comprising at least 15 contiguous nucleotides of SEQ ID NO: 128 or comprising SEQ ID NO: 143 or 144. In other embodiments, the first primer comprises a sequence selected from the group consisting of SEQ ID NOs: 75-88; the second primer comprises a sequence selected from the group consisting of SEQ ID NOs: 129-144; and the probe comprises a sequence selected from the group consisting of SEQ ID NOs: 90-104. In additional embodiments, the 3′ end of the probe is directly or indirectly attached to the 5′ end of said first primer forming a primer-probe complex. In still further embodiments, the primer-probe complex can be detectably labeled. In additional embodiments, the reaction mixture further comprises a quencher oligonucleotide comprising SEQ ID NO: 123, 124, or 127, or comprising at least 15 contiguous nucleotides of SEQ ID NO: 105. In some embodiments, the sample comprises a food sample or a water sample.

In a further aspect, the invention relates to an isolated polynucleotide comprising a primer-probe complex, wherein said primer probe complex comprises:

-   -   (A) a primer region comprising a nucleic acid sequence         comprising at least 15 contiguous nucleotides of SEQ ID NO: 1         and a probe region comprising at least 15 contiguous nucleotides         of SEQ ID NO: 16;     -   (B) a primer region comprising SEQ ID NO: 48 and a probe region         comprising a nucleic acid sequence selected from the group         consisting of SEQ ID NOs: 49-52;     -   (C) a primer region comprising SEQ ID NO: 55, and a probe region         comprising SEQ ID NO: 56;     -   (D) a primer region comprising at least 15 contiguous         nucleotides of SEQ ID NO: 74 and a probe region comprising at         least 15 contiguous nucleotides of SEQ ID NO: 89;     -   (E) a primer region comprising SEQ ID NO: 120 and a probe region         comprising a nucleic acid sequence selected from the group         consisting of SEQ ID NOs: 121-122;     -   (F) a primer region comprising SEQ ID NO: 125 and a probe region         comprising SEQ ID NO: 126; and     -   (G) a primer region comprising at least 15 contiguous         nucleotides of SEQ ID NO: 145 and a probe region comprising at         least 15 contiguous nucleotides of SEQ ID NO: 160;         wherein said probe region and said primer region each have a 5′         and 3′ terminus, wherein said 3′ terminus of said probe region         is attached to said 5′ terminus of said primer region via a         linker moiety, and wherein said primer-probe complex further         comprises a detectable label.

In a further aspect, the invention relates to kits and reagent tablets for detection of STEC bacteria in a sample, comprising an isolated polynucleotide of the present invention.

A further aspect of the present invention is a method for detecting the presence of STEC bacteria in a sample, said sample comprising nucleic acids, said method comprising:

-   -   (a) providing a reaction mixture comprising suitable primer         pairs for amplification of at least a portion of:         -   (i) the eae gene; and         -   (ii) one or more of the Stx1A and Stx2A genes; and     -   (b) performing PCR amplification of said nucleic acids of said         sample using the reaction mixture of step (a); and     -   (c) detecting the amplification of step (b).         In certain examples, amplification of a portion of the eae gene         comprises amplification of at least a portion of SEQ ID NO: 688.         In other examples, amplification of a portion one or more of the         Stx1A and Stx2A genes comprises amplification of at least a         portion of one or both of SEQ ID NOs: 686 and 687. In certain         embodiments, the reaction mixture comprises suitable primer         pairs for amplification of at least a portion of all three of         SEQ ID NOs: 686-688.

In additional embodiments, the reaction mixture further comprises suitable primer pairs for amplification of at least a portion of one or more of the genes encoding the O26, O111, O121, O45, O103, O145, and O157 surface antigens. In certain examples, such amplification comprises amplification of one or more nucleic acid sequences selected from the group consisting of SEQ ID NOs: 689-696.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 686 comprises (A) a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 1-15 and 48, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 58-72; or (B) a first primer comprising SEQ ID NO: 55 and a second primer comprising SEQ ID NO: 73. In additional examples, the reaction mixture further comprises a probe, wherein: (I) where said first primer is selected from SEQ ID NOs: 1-15, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 31-47; (II) where said first primer comprises SEQ ID NO: 48, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 49-52; and (III) where said first primer comprises SEQ ID NO: 55, said probe comprises SEQ ID NO: 56. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 31-47, 53-54, and 57.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 687 comprises: (A) a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 74-88, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 128-142; (B) a first primer comprising SEQ ID NO: 120 and a second primer comprising SEQ ID NO: 143; or (C) a first primer comprising SEQ ID NO: 125 and a second primer comprising SEQ ID NO: 144. In additional examples, the reaction mixture further comprises a probe, wherein: (I) where said first primer is selected from SEQ ID NOs: 74-88, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 89-104; (II) where said first primer comprises SEQ ID NO: 120, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 121-122; and (III) where said first primer comprises SEQ ID NO: 125, said probe comprises SEQ ID NO: 126. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 105-119, 123-124, and 127.

In certain examples, a said suitable primer pair for amplification of SEQ ID NO: 688 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 145-159, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 191-205. In additional examples, the reaction mixture further comprises a probe, wherein the probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 160-175. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 176-190.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 689 comprises: (A) a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 206-220, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 258-272; (B) a first primer comprising SEQ ID NO: 251, and a second primer comprising SEQ ID NO: 273; or (C) a first primer comprising SEQ ID NO: 255, and a second primer comprising SEQ ID NO: 274. In additional examples, the reaction mixture further comprises a probe, wherein the probe comprises: (I) where said first primer is selected from SEQ ID NOs: 206-220, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 221-235; (II) where said first primer comprises SEQ ID NO: 251, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 252-253; and (III) where said first primer comprises SEQ ID NO: 255, said probe comprises SEQ ID NO: 256. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 236-250, 254, and 257.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 690 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 275-289 and 324, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs:327-341. In additional examples, the reaction mixture further comprises a probe, wherein the probe comprises: (I) where said first primer is selected from SEQ ID NOs: 275-289, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 290-306; and (II) where said first primer comprises SEQ ID NO: 324, said probe comprises SEQ ID NO: 325. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples. the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 307-323 and 326.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 691 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 342-356, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 393-407. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 357-374. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 375-392.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 692 comprises: (A) a first primer comprising SEQ ID NO: 456, and a second primer comprising SEQ ID NO: 480; (B) a first primer comprising SEQ ID NO: 459, and a second primer comprising SEQ ID NO: 481; or (C) a first primer comprising SEQ ID NO: 462, and a second primer comprising SEQ ID NO: 482. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises: (I) where said first primer comprises SEQ ID NO: 456, said probe comprises SEQ ID NO: 457; (II) where said first primer comprises SEQ ID NO: 459, said probe comprises of SEQ ID NO: 460; and (III) where said first primer comprises SEQ ID NO: 462, said probe comprises SEQ ID NO: 463. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 458, 461, and 464.

In certain examples, a said suitable primer pair for amplification of SEQ ID NO: 693 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 408-423, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 465-479. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 424-439. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 440-455.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 694 comprises: (A) a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 483-497 and 537, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 540-554; (B) a first primer comprising SEQ ID NO: 528, and a second primer comprising SEQ ID NO: 555; (C) a first primer comprising SEQ ID NO: 531, and a second primer comprising SEQ ID NO: 556; or (D) a first primer comprising SEQ ID NO: 534, and a second primer comprising SEQ ID NO: 557. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises: (I) where said first primer is selected from SEQ ID NOs: 483-497, said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 498-512; (II) where said first primer comprises SEQ ID NO: 528, said probe comprises SEQ ID NO: 529; (III) where said first primer comprises SEQ ID NO: 531, said probe comprises SEQ ID NO: 532; (IV) where said first primer comprises SEQ ID NO: 534, said probe comprises SEQ ID NO: 535; (V) where said first primer comprises SEQ ID NO: 537, said probe comprises SEQ ID NO: 538. In further examples, the 3′ end of the probe is attached to the 5′ end of the primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 513-527, 530, 533, 536, and 539.

In certain examples, a suitable primer pair for amplification of SEQ ID NO: 695 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 558-572, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 603-617. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 573-587. In further examples, the 3′ end of said probe is attached to the 5′ end of said primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 588-602.

In certain examples, a said suitable primer pair for amplification of SEQ ID NO: 696 comprises a first primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 618-633, and a second primer comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 671-685. In additional examples, the reaction mixture further comprises a probe, wherein said probe comprises a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 634-653. In further examples, the 3′ end of said probe is attached to the 5′ end of said primer forming a primer-probe complex. In still further examples, the primer-probe complex is detectably labeled. In additional examples, the reaction mixture further comprises a quencher oligonucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 654-670.

In one particular embodiment:

-   -   (A) a suitable primer pair for amplification of SEQ ID NO: 686         comprises         -   (I) a first primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 1-15 and             48, and a second primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 58-72; or         -   (II) a first primer comprising SEQ ID NO: 55 and a second             primer comprising SEQ ID NO: 73;     -   (B) a suitable primer pair for amplification of SEQ ID NO: 687         comprises         -   (I) a first primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 74-88, and             a second primer comprising a nucleic acid sequence selected             from the group consisting of SEQ ID NOs: 128-142;         -   (II) a first primer comprising SEQ ID NO: 120 and a second             primer comprising SEQ ID NO: 143; or         -   (III) a first primer comprising SEQ ID NO: 125 and a second             primer comprising SEQ ID NO: 144;     -   (C) a suitable primer pair for amplification of SEQ ID NO: 688         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 145-159, and a         second primer comprising a nucleic acid sequence selected from         the group consisting of SEQ ID NOs: 191-205;     -   (D) a suitable primer pair for amplification of SEQ ID NO: 689         comprises         -   (I) a first primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 206-220,             and a second primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 258-272;         -   (II) a first primer comprising SEQ ID NO: 251, and a second             primer comprising SEQ ID NO: 273; or         -   (III) a first primer comprising SEQ ID NO: 255, and a second             primer comprising SEQ ID NO: 274;     -   (E) a suitable primer pair for amplification of SEQ ID NO: 690         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 275-289 and         324, and a second primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 327-341;     -   (F) a suitable primer pair for amplification of SEQ ID NO: 691         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 342-356, and a         second primer comprising a nucleic acid sequence selected from         the group consisting of SEQ ID NOs: 393-407;     -   (G) a suitable primer pair for amplification of SEQ ID NO: 692         comprises         -   (I) a first primer comprising SEQ ID NO: 456, and a second             primer comprising SEQ ID NO: 480;         -   (II) a first primer comprising SEQ ID NO: 459, and a second             primer comprising SEQ ID NO: 481; or         -   (III) a first primer comprising SEQ ID NO: 462, and a second             primer comprising SEQ ID NO: 482;     -   (H) a suitable primer pair for amplification of SEQ ID NO: 693         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 408-423, and a         second primer comprising a nucleic acid sequence selected from         the group consisting of SEQ ID NOs: 465-479;     -   (I) a suitable primer pair for amplification of SEQ ID NO: 694         comprises         -   (I) a first primer comprising a nucleic acid sequence             selected from the group consisting of SEQ ID NOs: 483-497             and 537, and a second primer comprising a nucleic acid             sequence selected from the group consisting of SEQ ID NOs:             540-554;         -   (II) a first primer comprising SEQ ID NO: 528, and a second             primer comprising SEQ ID NO: 555;         -   (III) a first primer comprising SEQ ID NO: 531, and a second             primer comprising SEQ ID NO: 556; or         -   (IV) a first primer comprising SEQ ID NO: 534, and a second             primer comprising SEQ ID NO: 557;     -   (J) a suitable primer pair for amplification of SEQ ID NO: 695         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 558-572, and a         second primer comprising a nucleic acid sequence selected from         the group consisting of SEQ ID NOs: 603-617; and     -   (K) a suitable primer pair for amplification of SEQ ID NO: 696         comprises a first primer comprising a nucleic acid sequence         selected from the group consisting of SEQ ID NOs: 618-633, and a         second primer comprising a nucleic acid sequence selected from         the group consisting of SEQ ID NOs: 671-685.

In additional examples, the reaction mixture comprises suitable primer pairs for amplification of SEQ ID NOs: 686-688 and one or more of SEQ ID NOs: 689-696.

In particular examples, the sample comprises a food sample or a water sample.

In additional embodiments, the invention relates to an isolated polynucleotide comprising a nucleic acid sequence selected from the group consisting of SEQ ID NO: 1-685.

In other embodiments, the invention relates to an isolated polynucleotide comprising a primer-probe complex, wherein said primer probe complex comprises:

-   -   (A) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 1-15, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 16-30;     -   (B) a primer region comprising SEQ ID NO: 48, and a probe region         comprising a nucleic acid sequence selected from the group         consisting of SEQ ID NOs: 49-52;     -   (C) a primer region comprising SEQ ID NO: 55, and a probe region         comprising SEQ ID NO: 56;     -   (D) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 74-88, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 89-104;     -   (E) a primer region comprising SEQ ID NO: 120, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 121-122;     -   (F) a primer region comprising SEQ ID NO: 125, and a probe         region comprising SEQ ID NO: 126;     -   (G) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 145-159, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 160-175;     -   (H) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 206-220, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 221-235;     -   (I) a primer region comprising SEQ ID NO: 251, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 252-253;     -   (J) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NO: 255, and a probe region         comprising a nucleic acid sequence selected from the group         consisting of SEQ ID NO: 256;     -   (K) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 275-289, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 290-306;     -   (L) a primer region comprising SEQ ID NO: 324, and a probe         region comprising SEQ ID NO: 325;     -   (M) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 342-356, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 357-374;     -   (N) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 408-423, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 424-439;     -   (O) a primer region comprising SEQ ID NO: 456, and a probe         region comprising SEQ ID NOs: 457;     -   (P) a primer region comprising SEQ ID NO: 459, and a probe         region comprising SEQ ID NO: 460;     -   (Q) a primer region comprising SEQ ID NO: 462, and a probe         region comprising SEQ ID NO: 463;     -   (R) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 483-497, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 498-512;     -   (S) a primer region comprising SEQ ID NO: 528, and a probe         region comprising SEQ ID NO: 529;     -   (T) a primer region comprising SEQ ID NO: 531, and a probe         region comprising SEQ ID NO: 532;     -   (U) a primer region comprising SEQ ID NO: 534, and a probe         region comprising SEQ ID NO: 535;     -   (V) a primer region comprising SEQ ID NO: 537, and a probe         region comprising SEQ ID NO: 538;     -   (W) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 558-572, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 573-587;     -   (X) a primer region comprising a nucleic acid sequence selected         from the group consisting of SEQ ID NOs: 618-633, and a probe         region comprising a nucleic acid sequence selected from the         group consisting of SEQ ID NOs: 634-653.         In certain examples, the probe region and primer region each         have a 5′ and 3′ terminus, wherein the 3′ terminus of the probe         region is attached to the 5′ terminus of the primer region via a         linker moiety. In other examples, the primer-probe complex         further comprises a detectable label.

In still further embodiments, the invention relates to a kit for detection of STEC bacteria in a sample, comprising an isolated polynucleotide of the present application. In other embodiments, the invention relates to a reagent tablet comprising a replication composition of the present application.

SUMMARY OF THE SEQUENCES

SEQ ID NOs: 1-30 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx1A gene target, such as the target sequence provided herein as SEQ ID NO: 686. Amplification using a primer selected from SEQ ID NOs: 1-30 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 58-72. In certain embodiments, one of SEQ ID NOs: 1-15 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 16-30. In certain other embodiments, the 3′terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 31-47.

SEQ ID NOs: 48-52 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx1A gene target, such as the target sequence provided herein as SEQ ID NO: 686. Amplification using a primer selected from SEQ ID NOs: 48-52 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 58-72. In certain embodiments, SEQ ID NO: 48 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 49-52. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 53-54.

SEQ ID NOs: 55-56 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx1A gene target, such as the target sequence provided herein as SEQ ID NO: 686. Amplification using a primer selected from SEQ ID NOs: 55-56 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 73. In certain embodiments, SEQ ID NO: 55 is used as a primer in conjunction with a probe comprising SEQ ID NO: 56. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 56 probe is attached to the 5′ terminus of the SEQ ID NO: 55 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 57.

SEQ ID NOs: 74-104 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx2A gene target, such as the target sequence provided herein as SEQ ID NO: 687. Amplification using a primer selected from SEQ ID NOs: 74-104 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 128-142. In certain embodiments, one of SEQ ID NOs: 74-88 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 89-104. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 105-119.

SEQ ID NOs: 120-122 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx2A gene target, such as the target sequence provided herein as SEQ ID NO: 687. Amplification using a primer selected from SEQ ID NOs: 120-122 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 143. In certain embodiments, SEQ ID NO: 120 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 121-122. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 123-124.

SEQ ID NOs: 125-126 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli Stx2A gene target, such as the target sequence provided herein as SEQ ID NO: 687. Amplification using a primer selected from SEQ ID NOs: 125-126 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 144. In certain embodiments, SEQ ID NO: 125 is used as a primer in conjunction with a probe comprising SEQ ID NO: 126. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 126 probe is attached to the 5′ terminus of the SEQ ID NO: 125 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 127.

SEQ ID NOs: 145-175 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli eae gene target, such as the target sequence provided herein as SEQ ID NO: 688. Amplification using a primer selected from SEQ ID NOs: 145-175 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 191-205. In certain embodiments, one of SEQ ID NOs: 145-159 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 160-175. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 176-190.

SEQ ID NOs: 206-235 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O26 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 689. Amplification using a primer selected from SEQ ID NOs: 206-235 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 258-272. In certain embodiments, one of SEQ ID NOs: 206-220 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 221-235. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 236-250.

SEQ ID NOs: 251-253 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O26 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 689. Amplification using a primer selected from SEQ ID NOs: 251-253 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 273. In certain embodiments, SEQ ID NO: 251 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 252-253. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the SEQ ID NO: 251 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 254.

SEQ ID NOs: 255-256 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O26 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 689. Amplification using a primer selected from SEQ ID NOs: 255-256 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 274. In certain embodiments, SEQ ID NO: 255 is used as a primer in conjunction with a probe comprising SEQ ID NO: 256. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 256 probe is attached to the 5′ terminus of the SEQ ID NO: 255 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 257.

SEQ ID NOs: 275-306 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli S0111 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 690. Amplification using a primer selected from SEQ ID NOs: 275-306 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 327-341. In certain embodiments, one of SEQ ID NOs: 275-289 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 290-306. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 307-323.

SEQ ID NOs: 324-325 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli S0111 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 690. Amplification using a primer selected from SEQ ID NOs: 324-325 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 327-341. In certain embodiments, SEQ ID NO: 324 is used as a primer in conjunction with a probe comprising SEQ ID NO: 325. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 325 probe is attached to the 5′ terminus of the SEQ ID NO: 324 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 326.

SEQ ID NOs: 342-374 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O121 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 691. Amplification using a primer selected from SEQ ID NOs: 342-374 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 393-407. In certain embodiments, one of SEQ ID NOs: 342-356 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 357-374. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 375-392.

SEQ ID NOs: 408-439 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O45 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 693. Amplification using a primer selected from SEQ ID NOs: 408-439 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 465-479. In certain embodiments, one of SEQ ID NOs: 408-423 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 424-439. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 440-455.

SEQ ID NOs: 456-457 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O45 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 692. Amplification using a primer selected from SEQ ID NOs: 456-457 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 480. In certain embodiments, SEQ ID NO: 456 is used as a primer in conjunction with a probe comprising SEQ ID NO: 457. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 457 probe is attached to the 5′ terminus of the SEQ ID NO: 456 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 458.

SEQ ID NOs: 459-460 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O45 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 692. Amplification using a primer selected from SEQ ID NOs: 459-460 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 481. In certain embodiments, SEQ ID NO: 459 is used as a primer in conjunction with a probe comprising SEQ ID NO: 460. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 460 probe is attached to the 5′ terminus of the SEQ ID NO: 459 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 461.

SEQ ID NOs: 462-464 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O45 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 692. Amplification using a primer selected from SEQ ID NOs: 464-464 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 482. In certain embodiments, SEQ ID NO: 462 is used as a primer in conjunction with a probe comprising SEQ ID NO: 463. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 463 probe is attached to the 5′ terminus of the SEQ ID NO: 462 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 464.

SEQ ID NOs: 483-512 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O103 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 694. Amplification using a primer selected from SEQ ID NOs: 483-512 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 540-554. In certain embodiments, one of SEQ ID NOs: 483-497 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 498-512. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 513-527.

SEQ ID NOs: 528-529 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O103 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 694. Amplification using a primer selected from SEQ ID NOs: 528-529 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 555. In certain embodiments, SEQ ID NO: 528 is used as a primer in conjunction with a probe comprising SEQ ID NO: 529. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 529 probe is attached to the 5′ terminus of the SEQ ID NO: 528 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 530.

SEQ ID NOs: 531-532 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O103 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 694. Amplification using a primer selected from SEQ ID NOs: 531-532 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 556. In certain embodiments, SEQ ID NO: 531 is used as a primer in conjunction with a probe comprising SEQ ID NO: 532. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 532 probe is attached to the 5′ terminus of the SEQ ID NO: 531 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 533.

SEQ ID NOs: 534-535 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O103 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 694. Amplification using a primer selected from SEQ ID NOs: 534-535 can be performed in conjunction with a suitable reverse primer, such as SEQ ID NO: 557. In certain embodiments, SEQ ID NO: 534 is used as a primer in conjunction with a probe comprising SEQ ID NO: 535. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 535 probe is attached to the 5′ terminus of the SEQ ID NO: 534 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 536.

SEQ ID NOs: 537-538 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O103 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 694. Amplification using a primer selected from SEQ ID NOs: 537-538 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 540-554. In certain embodiments, SEQ ID NO: 537 is used as a primer in conjunction with a probe comprising SEQ ID NO: 538. In certain other embodiments, the 3′ terminus of the SEQ ID NO: 538 probe is attached to the 5′ terminus of the SEQ ID NO: 537 primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as SEQ ID NO: 539.

SEQ ID NOs: 558-587 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O145 surface antigen gene target, such as the target sequence provided herein as SEQ ID NO: 695. Amplification using a primer selected from SEQ ID NOs: 558-587 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 603-617. In certain embodiments, one of SEQ ID NOs: 558-572 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 573-587. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 588-602.

SEQ ID NOs: 618-653 are nucleotide sequences capable of use as primers or probes for amplifying and detecting a portion of an E. coli O157 prophage pathogenicity factor gene target, such as the target sequence provided herein as SEQ ID NO: 696. Amplification using a primer selected from SEQ ID NOs: 618-653 can be performed in conjunction with a suitable reverse primer, such as one selected from SEQ ID NOs: 671-685. In certain embodiments, one of SEQ ID NOs: 618-633 is used as a primer in conjunction with a probe selected from SEQ ID NOs: 634-653. In certain other embodiments, the 3′ terminus of the selected probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled and is used in conjunction with a separate quencher oligonucleotide capable of hybridizing to the probe and quenching its fluorescence, such as an oligonucleotide selected from SEQ ID NOs: 654-670.

SEQ ID NO: 686 is the nucleotide sequence of a portion of an E. coli Stx1A gene that is useful for detecting the presence of the Stx1A gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 686 include SEQ ID NOs: 1-30, 48-52, 55-56, and 58-73. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 1-15 and a reverse primer selected from SEQ ID NOs: 58-72, while detection is accomplished using a probe selected from SEQ ID NOs: 16-30 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 31-47. In other embodiments, amplification is performed using SEQ ID NO: 48 as a forward primer and a reverse primer selected from SEQ ID NOs: 58-72, while detection is accomplished using a probe selected from SEQ ID NOs: 49-52 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 53-54. In still further embodiments, amplification is performed using SEQ ID NO: 55 as a forward primer and SEQ ID NO: 73 as a reverse primer, while detection is accomplished using SEQ ID NO: 56 as a probe and, optionally, SEQ ID NO: 57 as a quencher oligonucleotide.

SEQ ID NO: 687 is the nucleotide sequence of a portion of an E. coli Stx2A gene that is useful for detecting the presence of the Stx2A gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 687 include SEQ ID NOs: 74-104, 120-122, 125-126, and 128-144. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 74-88 and a reverse primer selected from SEQ ID NOs: 128-142, while detection is accomplished using a probe selected from SEQ ID NOs: 89-104 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 105-119. In other embodiments, amplification is performed using SEQ ID NO: 120 as a forward primer and SEQ ID NO: 143 as a reverse primer, while detection is accomplished using a probe selected from SEQ ID NOs: 121-122 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 123-124. In still further embodiments, amplification is performed using SEQ ID NO: 125 as a forward primer and SEQ ID NO: 144 as a reverse primer, while detection is accomplished using SEQ ID NO: 126 as a probe and, optionally, SEQ ID NO: 127 as a quencher oligonucleotide.

SEQ ID NO: 688 is the nucleotide sequence of a portion of an E. coli eae gene that is useful for detecting the presence of the eae gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 688 include SEQ ID NOs: 145-175. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 145-159 and a reverse primer selected from SEQ ID NOs: 191-205, while detection is accomplished using a probe selected from SEQ ID NOs: 160-175 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 176-190.

SEQ ID NO: 689 is the nucleotide sequence of a portion of an E. coli O26 surface antigen gene that is useful for detecting the presence of the 026 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 689 include SEQ ID NOs: 206-235, 251-253, 255-256, and 258-274. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 206-220 and a reverse primer selected from SEQ ID NOs: 258-272, while detection is accomplished using a probe selected from SEQ ID NOs: 221-235 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 236-250. In other embodiments, amplification is performed using SEQ ID NO: 251 as a forward primer and SEQ ID NO: 273 as a reverse primer, while detection is accomplished using a probe selected from SEQ ID NOs: 252-253 and, optionally, SEQ ID NO: 254 as a quencher oligonucleotide. In still further embodiments, amplification is performed using SEQ ID NO: 255 as a forward primer and SEQ ID NO: 274 as a reverse primer, while detection is accomplished using SEQ ID NO: 256 as a probe and, optionally, SEQ ID NO: 257 as a quencher oligonucleotide.

SEQ ID NO: 690 is the nucleotide sequence of a portion of an E. coli O111 surface antigen gene that is useful for detecting the presence of the 0111 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 690 include SEQ ID NOs: 275-306, 324-325, and 327-341. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 275-289 and a reverse primer selected from SEQ ID NOs: 327-341, while detection is accomplished using a probe selected from SEQ ID NOs: 290-306 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 307-323. In other embodiments, amplification is performed using SEQ ID NO: 324 as a forward primer and a reverse primer selected from SEQ ID NOs: 327-341, while detection is accomplished using a probe comprising SEQ ID NO: 325 and, optionally, a quencher oligonucleotide comprising SEQ ID NO: 326.

SEQ ID NO: 691 is the nucleotide sequence of a portion of an E. coli O121 surface antigen gene that is useful for detecting the presence of the 0121 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 691 include SEQ ID NOs: 342-356 and 393-407. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 342-356 and a reverse primer selected from SEQ ID NOs: 393-407, while detection is accomplished using a probe selected from SEQ ID NOs: 357-374 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 375-392.

SEQ ID NO: 692 is the nucleotide sequence of a portion of an E. coli O45 surface antigen gene that is useful for detecting the presence of the O45 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 692 include SEQ ID NOs: 456-457, 459-460, 462-463, and 480-482. In certain embodiments, amplification is performed using SEQ ID NO: 456 as a forward primer and SEQ ID NO: 480 as a reverse primer, while detection is accomplished using a probe comprising SEQ ID NO: 457 and, optionally, a quencher oligonucleotide comprising SEQ ID NO: 458. In further embodiments, amplification is performed using SEQ ID NO: 459 as a forward primer and SEQ ID NO: 481 as a reverse primer, while detection is accomplished using a probe comprising SEQ ID NO: 460 and, optionally, a quencher oligonucleotide comprising SEQ ID NO: 461. In still further embodiments, amplification is performed using SEQ ID NO: 462 as a forward primer and SEQ ID NO: 482 as a reverse primer, while detection is accomplished using a probe comprising SEQ ID NO: 463 and, optionally, a quencher oligonucleotide comprising SEQ ID NO: 464.

SEQ ID NO: 693 is the nucleotide sequence of a portion of an E. coli O45 surface antigen gene that is useful for detecting the presence of the O45 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 692 include SEQ ID NOs: 408-439 and 465-479. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 408-423 and a reverse primer selected from SEQ ID NOs: 465-479, while detection is accomplished using a probe selected from SEQ ID NOs: 424-439 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 44-455.

SEQ ID NO: 694 is the nucleotide sequence of a portion of an E. coli O103 surface antigen gene that is useful for detecting the presence of the 0103 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 694 include SEQ ID NOs: 483-512, 528-529, 531-532, 534-535, 537-538, and 540-557. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 483-497 and a reverse primer selected from SEQ ID NOs: 550-554, while detection is accomplished using a probe selected from SEQ ID NOs: 498-512 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 513-527. In other embodiments, amplification is performed using SEQ ID NO: 528 as a forward primer and SEQ ID NO: 555 as a reverse primer, while detection is accomplished using SEQ ID NO: 529 as a probe and, optionally, a SEQ ID NO: 530 as a quencher oligonucleotide. In still further embodiments, amplification is performed using SEQ ID NO: 531 as a forward primer and SEQ ID NO: 556 as a reverse primer, while detection is accomplished using SEQ ID NO: 532 as a probe and, optionally, SEQ ID NO: 533 as a quencher oligonucleotide. In additional embodiments, amplification is performed using SEQ ID NO: 534 as a forward primer and SEQ ID NO: 557 as a reverse primer, while detection is accomplished using SEQ ID NO: 535 as a probe and, optionally, SEQ ID NO: 536 as a quencher oligonucleotide. In yet further embodiments, amplification is performed using SEQ ID NO: 537 as a forward primer and a reverse primer selected from SEQ ID NOs: 550-554, while detection is accomplished using SEQ ID NO: 538 as a probe and, optionally, SEQ ID NO: 539 as a quencher oligonucleotide.

SEQ ID NO: 695 is the nucleotide sequence of a portion of an E. coli O145 surface antigen gene that is useful for detecting the presence of the 0145 surface antigen gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 695 include SEQ ID NOs: 558-587 and 603-617. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 558-572 and a reverse primer selected from SEQ ID NOs: 603-617, while detection is accomplished using a probe selected from SEQ ID NOs: 573-587 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 588-602.

SEQ ID NO: 696 is the nucleotide sequence of a portion of an E. coli O157 prophage pathogenicity factor gene that is useful for detecting the presence of the O157 prophage pathogenicity factor gene in a sample, and, ultimately, the presence of STEC bacteria in a sample. Suitable primers useful for amplification of SEQ ID NO: 696 include SEQ ID NOs: 618-653 and 671-685. In certain embodiments, amplification is performed with a forward primer selected from SEQ ID NOs: 618-633 and a reverse primer selected from SEQ ID NOs: 671-685, while detection is accomplished using a probe selected from SEQ ID NOs: 634-653 and, optionally, a quencher oligonucleotide selected from SEQ ID NOs: 654-670.

SEQ ID NOs: 697-700 comprise nucleotide sequences useful for amplifying SV40 DNA, which, in some examples, is employed as a positive control reaction. In certain examples, amplification is performed using SEQ ID NO: 697 or 698 as a forward primer in conjunction with SEQ ID NO: 700 as a reverse primer. In certain embodiments, one of SEQ ID NOs: 697 or 698 is used as a primer in conjunction with SEQ ID NO: 699 as a probe. In certain other embodiments, the 3′ terminus the SEQ ID NO: 699 probe is attached to the 5′ terminus of the selected primer via a suitable linker moiety, such as an 18-carbon spacer. In additional embodiments, the probe is detectably labeled with a reporter-quencher pair and possesses self-complementary sequences flanking the probe region, thereby allowing the nucleic acid molecule to self-hybridize into a stem-loop structure, thus allowing for quenching of the reporter signal by the quencher molecule.

The sequences conform with 37 C.F.R. §§1.821-1.825 (“Requirements for Patent Applications Containing Nucleotide Sequences and/or Amino Acid Sequence Disclosures—the Sequence Rules”) and are consistent with World Intellectual Property Organization (WIPO) Standard ST.25 (1998) and the sequence listing requirements of the EPO and PCT (Rules 5.2 and 49.5(a-bis), and Section 208 and Annex C of the Administrative Instructions). The symbols and format used for nucleotide and amino acid sequence data comply with the rules set forth in 37 C.F.R. §1.822.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Applicants specifically incorporate the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

DEFINITIONS

In this disclosure, a number of terms and abbreviations are used. The following definitions are provided.

As used herein, the term “about” or “approximately” means within 20%, preferably within 10%, and more preferably within 5% of a given value or range.

The term “comprising” is intended to include embodiments encompassed by the terms “consisting essentially of” and “consisting of:” Similarly, the term “consisting essentially of” is intended to include embodiments encompassed by the term “consisting of:”

“Polymerase chain reaction” is abbreviated PCR.

The term “isolated” refers to materials, such as nucleic acid molecules and/or proteins, which are substantially free or otherwise removed from components that normally accompany or interact with the materials in a naturally occurring environment. Isolated polynucleotides may be purified from a host cell in which they naturally occur. Conventional nucleic acid purification methods known to skilled artisans may be used to obtain isolated polynucleotides. The term also embraces recombinant polynucleotides and chemically synthesized polynucleotides.

The terms “polynucleotide,” “polynucleotide sequence,” “nucleic acid sequence,” “nucleic acid fragment,” and “oligonucleotide” are used interchangeably herein. These terms encompass nucleotide sequences and the like. A polynucleotide may be a polymer of RNA or DNA that is single- or double-stranded, that optionally contains synthetic, non-natural, or altered nucleotide bases. A polynucleotide in the form of a polymer of DNA may be comprised of one or more strands of cDNA, genomic DNA, synthetic DNA, or mixtures thereof.

The term “amplification product” or “amplicon” refers to nucleic acid fragments produced during a primer-directed amplification reaction. Typical methods of primer-directed amplification include polymerase chain reaction (PCR), ligase chain reaction (LCR), or strand displacement amplification (SDA). If PCR methodology is selected, the replication composition may comprise the components for nucleic acid replication, for example: nucleotide triphosphates, two (or more) primers with appropriate sequences, thermostable polymerase, buffers, solutes, and proteins. These reagents and details describing procedures for their use in amplifying nucleic acids are provided in U.S. Pat. No. 4,683,202 (1987, Mullis, et al.) and U.S. Pat. No. 4,683,195 (1986, Mullis, et al.). If LCR methodology is selected, then the nucleic acid replication compositions may comprise, for example: a thermostable ligase (e.g., Thermus aquaticus ligase), two sets of adjacent oligonucleotides (wherein one member of each set is complementary to each of the target strands), Tris-HCl buffer, KCl, EDTA, NAD, dithiothreitol, and salmon sperm DNA. See, for example, Tabor et al., Proc. Natl. Acad. Sci. U.S.A. 82:1074-1078 (1985).

The term “primer” refers to an oligonucleotide (synthetic or occurring naturally) that is capable of acting as a point of initiation of nucleic acid synthesis or replication along a complementary strand when placed under conditions in which synthesis of a complementary strand is catalyzed by a polymerase. A primer can further contain a detectable label, for example a 5′ end label. In certain embodiments, primers of the present invention are 8-60 nucleic acids in length. In other embodiments, primers are 10-50, 14-40, or 20-30 nucleic acids in length. In particular embodiments, a primer is at least about 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 49, or 60 nucleotides in length.

The term “probe” refers to an oligonucleotide (synthetic or occurring naturally) that is complementary (though not necessarily fully complementary) to a polynucleotide of interest and forms a duplexed structure by hybridization with at least one strand of the polynucleotide of interest. A probe or primer-probe complex can further contain a detectable label. In certain embodiments, probes of the present invention are 8-60 nucleic acids in length. In other embodiments, probes are 10-50, 14-40, or 20-30 nucleic acids in length. In particular embodiments, a probe is at least about 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 49, or 60 nucleotides in length.

A probe can either be an independent entity or complexed with or otherwise attached to a primer, such as where a probe is connected via its 3′ terminus to a primer's 5′ terminus. Such an attachment can be either direct or indirect, such as when the attachment is accomplished through a linker, which may be a nucleotide or non-nucleotide linker and which may be a non-amplifiable linker, such as a hexethylene glycol (HEG) or 18-carbon linker. In such a case, this would be termed a “primer-probe complex.” One example of such a primer-probe complex can be found in U.S. Pat. No. 6,326,145, incorporated herein by reference in its entirety, which are frequently referred to as “Scorpion probes” or “Scorpion primers.”

As used herein, the terms “label” and “detectable label” refer to a molecule capable of detection, including, but not limited to, radioactive isotopes, fluorescers, chemiluminescers, enzymes, enzyme substrates, enzyme cofactors, enzyme inhibitors, chromophores, dyes, metal ions, metal sols, semiconductor nanocrystals, ligands (e.g., biotin, avidin, streptavidin, or haptens), and the like. A detectable label can also include a combination of a reporter and a quencher.

The term “reporter” refers to a substance or a portion thereof which is capable of exhibiting a detectable signal, which signal can be suppressed by a quencher. The detectable signal of the reporter is, e.g., fluorescence in the detectable range. The term “quencher” refers to a substance or portion thereof which is capable of suppressing, reducing, inhibiting, etc., the detectable signal produced by the reporter.

As used herein, the terms “quenching” and “fluorescence energy transfer” refer to the process whereby, when a reporter and a quencher are in close proximity, and the reporter is excited by an energy source, a substantial portion of the energy of the excited state nonradiatively transfers to the quencher where it either dissipates nonradiatively or is emitted at a different emission wavelength than that of the reporter.

Preferably, the reporter may be selected from fluorescent organic dyes modified with a suitable linking group for attachment to the oligonucleotide, such as to the terminal 3′ carbon or terminal 5′ carbon. The quencher may also be selected from organic dyes, which may or may not be fluorescent, depending on the embodiment of the present invention. Generally, whether the quencher is fluorescent or simply releases the transferred energy from the reporter by non-radiative decay, the absorption band of the quencher should at least substantially overlap the fluorescent emission band of the reporter to optimize the quenching. Non-fluorescent quenchers or dark quenchers typically function by absorbing energy from excited reporters, but do not release the energy radiatively.

Selection of appropriate reporter-quencher pairs for particular probes may be undertaken in accordance with known techniques. Fluorescent and dark quenchers and their relevant optical properties from which exemplary reporter-quencher pairs may be selected are listed and described, for example, in Berlman, Handbook of Fluorescence Spectra of Aromatic Molecules, 2nd ed., Academic Press, New York, 1971, the content of which is incorporated herein by reference. Examples of modifying reporters and quenchers for covalent attachment via common reactive groups that can be added to an oligonucleotide in the present invention may be found, for example, in Haugland, Handbook of Fluorescent Probes and Research Chemicals, Molecular Probes of Eugene, Oreg., 1992, the content of which is incorporated herein by reference.

Preferred reporter-quencher pairs may be selected from xanthene dyes including fluoresceins and rhodamine dyes. Many suitable forms of these compounds are available commercially with substituents on the phenyl groups, which can be used as the site for bonding or as the bonding functionality for attachment to an oligonucleotide. Another preferred group of fluorescent compounds for use as reporters are the naphthylamines, having an amino group in the alpha or beta position. Included among such naphthylamino compounds are 1-dimethylaminonaphthyl-5 sulfonate, 1-anilino-8-naphthalene sulfonate and 2-p-touidinyl-6-naphthalene sulfonate. Other dyes include 3-phenyl-7-isocyanatocoumarin; acridines such as 9-isothiocyanatoacridine; N-(p-(2-benzoxazolyl)phenyl)maleimide; benzoxadiazoles; stilbenes; pyrenes and the like.

Most preferably, the reporters and quenchers are selected from fluorescein and rhodamine dyes. These dyes and appropriate linking methodologies for attachment to oligonucleotides are well known in the art.

Suitable examples of quenchers may be selected from 6-carboxy-tetramethyl-rhodamine, 4-(4-dimethylaminophenylazo) benzoic acid (DABYL), tetramethylrhodamine (TAMRA), BHQ-0™, BHQ-1™, BHQ-2™, and BHQ-3™, each of which are available from Biosearch Technologies, Inc. of Novato, Calif., QSY-7™, QSY-9™, QSY-21™ and QSY-35™, each of which are available from Molecular Probes, Inc., and the like.

Suitable examples of reporters may be selected from dyes such as SYBR green, 5-carboxyfluorescein (5-FAM™ available from Applied Biosystems of Foster City, Calif.), 6-carboxyfluorescein (6-FAM), tetrachloro-6-carboxyfluorescein (TET), 2,7-dimethoxy-4,5-dichloro-6-carboxyfluorescein, hexachloro-6-carboxyfluorescein (HEX), 6-carboxy-2′,4,7,7′-tetrachlorofluorescein (6-TET™ available from Applied Biosystems), carboxy-X-rhodamine (ROX), 6-carboxy-4′,5′-dichloro-2′,7′-dimethoxyfluorescein (6-JOE™ available from Applied Biosystems), VIC™ dye products available from Molecular Probes, Inc., NED™ dye products available from available from Applied Biosystems, and the like.

One example of a probe which contains a reporter and a quencher is a Scorpion probe in either a unimolecular or bimolecular conformation. In a unimolecular Scorpion, the probe portion of the primer-probe complex is flanked by self-complementary regions which allow the probe to form into a stem-loop structure when the probe is unbound from its target DNA. Further, in a unimolecular Scorpion, a reporter is typically attached at or near one of the self-complementary regions, such as at the 5′ terminus of the Scorpion probe, and a quencher is attached at or near the other self-complementary region, such as immediately 5′ to the non-amplifiable linker, such that the quencher is in sufficiently close proximity to the reporter to cause quenching when the probe is in its stem-loop conformation. In a bimolecular Scorpion, self-complementary flanking regions are not typically employed, but rather a separate “blocking oligonucleotide” or “quenching oligonucleotide” is employed in conjunction with the Scorpion probe. This blocking oligonucleotide is capable of hybridizing to the probe region of the Scorpion probe when the probe is unbound from its target DNA. Further, in a bimolecular Scorpion, the reporter is typically attached to the probe region of the Scorpion probe, such as at the 5′ terminus of the Scorpion probe, while the quencher is attached to the blocking oligonucleotide, such as at the 3′ terminus of the blocking oligonucleotide, such that the quencher is in sufficiently close proximity to the reporter to cause quenching when the probe is unbound from its target DNA and is instead hybridized to the blocking oligonucleotide.

Another example of a probe which contains a reporter and a quencher is a probe that is to be used in a 5′-exonuclease assay, such as the Taqman® real-time PCR technique. In this context, the oligonucleotide probe will have a sufficient number of phosphodiester linkages adjacent to its 5′ end so that the 5′ to 3′ nuclease activity employed can efficiently degrade the bound probe to separate the reporters and quenchers. Yet another example of a probe which contains a reporter and quencher is a Molecular Beacon type probe, which contains a probe region flanked by self-complementary regions that allow the probe to form a stem-loop structure when unbound from the probe's target sequence. Such probes typically have a reporter attached at or near one terminus and a quencher attached at or near the other terminus such that the quencher is in sufficiently close proximity to the reporter to cause quenching when the probe is in its unbound, and thus stem-loop, form.

The term “replication inhibitor moiety” refers to any atom, molecule or chemical group that is attached to the 3′ terminal hydroxyl group of an oligonucleotide that will block the initiation of chain extension for replication of a nucleic acid strand. Examples include, but are not limited to: 3′-deoxynucleotides (e.g., cordycepin), dideoxynucleotides, phosphate, ligands (e.g., biotin and dinitrophenol), reporter molecules (e.g., fluorescein and rhodamine), carbon chains (e.g., propanol), a mismatched nucleotide or polynucleotide, or peptide nucleic acid units. The term “non-participatory” refers to the lack of participation of a probe or primer in a reaction for the amplification of a nucleic acid molecule. Specifically a non-participatory probe or primer is one that will not serve as a substrate for, or be extended by, a DNA or RNA polymerase. A “non-participatory probe” is inherently incapable of being chain extended by a polymerase. It may or may not have a replication inhibitor moiety.

A nucleic acid molecule is “hybridizable” to another nucleic acid molecule, such as a cDNA, genomic DNA, or RNA, when a single stranded form of the nucleic acid molecule can anneal to the other nucleic acid molecule under the appropriate conditions of temperature and solution ionic strength. Hybridization and washing conditions are well known and exemplified, for example, in Sambrook, J., Fritsch, E. F. and Maniatis, T., Molecular Cloning: A Laboratory Manual, 2nd ed., Cold Spring Harbor Laboratory Cold Spring Harbor, N.Y. (1989), particularly Chapter 11 and Table 11.1 therein (entirely incorporated herein by reference). The conditions of temperature and ionic strength determine the “stringency” of the hybridization. For preliminary screening for homologous nucleic acids, low stringency hybridization conditions, corresponding to a Tm of 55° C., can be used, e.g., 5×SSC, 0.1% SDS, 0.25% milk, and no formamide; or 30% formamide, 5×SSC, 0.5% SDS. Moderate stringency hybridization conditions correspond to a higher Tm, e.g., 40% formamide, with 5× or 6×SSC. Hybridization requires that the two nucleic acids contain complementary sequences, although, depending on the stringency of the hybridization, mismatches between bases are possible. The appropriate stringency for hybridizing nucleic acids depends on the length of the nucleic acids and the degree of complementation, variables well known in the art. The greater the degree of similarity or homology between two nucleotide sequences, the greater the value of Tm for hybrids of nucleic acids having those sequences. The relative stability (corresponding to higher Tm) of nucleic acid hybridizations decreases in the following order: RNA:RNA, DNA:RNA, DNA:DNA. For hybrids of greater than 100 nucleotides in length, equations for calculating Tm have been derived (see Sambrook et al., supra, 9.50-9.51). For hybridizations with shorter nucleic acids, i.e., oligonucleotides, the position of mismatches becomes more important, and the length of the oligonucleotide determines its specificity (see Sambrook et al., supra, 11.7-11.8). In one preferred embodiment, the length for a hybridizable nucleic acid is at least about 10 nucleotides. More preferably a minimum length for a hybridizable nucleic acid is at least about 11 nucleotides, at least about 12 nucleotides, at least about 13 nucleotides, at least about 14 nucleotides, at least about 15 nucleotides, at least about 16 nucleotides, at least about 17 nucleotides, at least about 18 nucleotides, at least about 19 nucleotides, at least about 20 nucleotides, at least about 21 nucleotides, at least about 22 nucleotides, at least about 23 nucleotides, at least about 24 nucleotides, at least about 25 nucleotides, at least about 26 nucleotides, at least about 27 nucleotides, at least about 28 nucleotides, at least about 29 nucleotides, or, most preferably, at least 30 nucleotides. Furthermore, the skilled artisan will recognize that the temperature and wash solution salt concentration may be adjusted as necessary according to factors such as length of the probe.

Standard recombinant DNA and molecular cloning techniques used here are well known in the art and are described by, e.g., Sambrook et al. (supra); and by Ausubel, F. M. et al., Current Protocols in Molecular Biology, published by Greene Publishing Assoc. and Wiley-Interscience (1987).

Oligonucleotides

Methods have been developed for detecting STEC bacteria by detecting one or more gene targets selected from Stx1A, Stx2A, eae, O26, O111, O121, O45, O103, O145, and O157. In certain embodiments, the methods involve detecting one or both of Stx1A and Stx2A, as well as detecting eae, and, optionally, one or more of O26, O111, O121, O45, O103, O145, and O157. In still further embodiments, the methods involve detecting one or more of SEQ ID NOs: 686-688. In certain embodiments, the method involves detecting one or both of SEQ ID NOs: 686-687, as well as detecting SEQ ID NO: 688, and, optionally, one or more of SEQ ID NOs: 689-696. Oligonucleotides have been developed for the detection of such nucleotide sequences and the subsequent detection and identification of STEC bacteria, including forward and reverse primers, probes, and quencher oligonucleotides. Oligonucleotides of the instant invention may be used as primers for PCR amplification. Exemplary primer pairs and their corresponding targets, blocking oligonucleotides, and probes are shown in Table 1.

TABLE 1 Target sequences and the primers, probes, and quenchers related thereto 5′ (Forward) Quencher 3′ (Reverse) Target Target Primer(s) Probe(s) Oligo(s) Primer(s) Gene Gene SEQ SEQ ID SEQ ID SEQ ID SEQ ID Name ID NO. NO(s) NO(s) NO(s) NO(s) Stx1A 686  1-15 16-30 41-47 58-72  48 49-52 53-54 58-72  55  56  57  73 Stx2A 687 74-88  89-104 105-119 128-142 120 121-122 123-124 143 125 126 127 144 Eae 688 145-159 160-175 176-190 191-205 O26 689 206-220 221-235 236-250 258-272 251 252-253 254 273 255 256 257 274 O111 690 275-289 290-306 307-323 327-341 324 325 326 327-341 O121 691 342-356 357-374 375-392 393-407 O45 692 456 457 458 480 459 460 461 481 462 463 464 482 693 408-423 424-439 440-455 465-479 O103 694 483-497 498-512 513-527 540-554 528 529 530 555 531 532 533 556 534 535 536 557 537 538 539 540-555 O145 695 558-572 573-587 588-602 603-617 O157 696 618-633 634-653 654-670 671-685 Each of these primers and probes was designed based on sequence analysis of its corresponding region of the E. coli genome.

In certain embodiments, a primer for amplifying and/or detecting SEQ ID NO: 686 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 1, 48, or 55, or a sequence complementary thereto. In other embodiments a probe for amplifying and/or detecting SEQ ID NO: 686 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 16, 49-52, or 56, or a sequence complementary thereto. In further embodiments, a quencher useful for quenching the signal of such a probe comprises at least about 15 contiguous nucleotides of SEQ ID NO: 41, 53, 54, or 57, or a sequence complementary thereto. In additional embodiments a second primer, or reverse primer, for amplifying and/or detecting SEQ ID NO: 686 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 58 or 73, or a sequence complementary thereto. In still further embodiments, at least about 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 contiguous nucleotides of these sequences could be used.

In certain embodiments, a primer for amplifying and/or detecting SEQ ID NO: 687 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 74, 120, or 125, or a sequence complementary thereto. In other embodiments a probe for amplifying and/or detecting SEQ ID NO: 687 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 89, 121, 122, or 126, or a sequence complementary thereto. In further embodiments, a quencher useful for quenching the signal of such a probe comprises at least about 15 contiguous nucleotides of SEQ ID NO: 105, 123, 124, or 127, or a sequence complementary thereto. In additional embodiments a second primer, or reverse primer, for amplifying and/or detecting SEQ ID NO: 687 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 128, 143, or 144, or a sequence complementary thereto. In still further embodiments, at least about 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 contiguous nucleotides of these sequences could be used.

In certain embodiments, a primer for amplifying and/or detecting SEQ ID NO: 688 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 145, or a sequence complementary thereto. In other embodiments a probe for amplifying and/or detecting SEQ ID NO: 688 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 160, or a sequence complementary thereto. In further embodiments, a quencher useful for quenching the signal of such a probe comprises at least about 15 contiguous nucleotides of SEQ ID NO: 176, or a sequence complementary thereto. In additional embodiments a second primer, or reverse primer, for amplifying and/or detecting SEQ ID NO: 688 comprises at least about 15 contiguous nucleotides of SEQ ID NO: 191, or a sequence complementary thereto. In still further embodiments, at least about 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or contiguous nucleotides of these sequences could be used.

These oligonucleotide primers may also be useful for other nucleic acid amplification methods such as the ligase chain reaction (LCR) (Backman et al., 1989, EP 0 320 308; Carrino et al., 1995, J. Microbiol. Methods 23: 3-20); nucleic acid sequence-based amplification (NASBA), (Carrino et al., 1995, supra); and self-sustained sequence replication (3SR) and ‘Q replicase amplification’ (Pfeffer et al., 1995 Veterinary Res. Comm. 19: 375-407).

The oligonucleotide primers of the present invention can also contain a detectable label, for example a 5′ end label.

In addition, oligonucleotides of the present invention also may be used as hybridization probes. Some examples of useful probes are provided in Table 1. Hybridization using DNA probes has been frequently used for the detection of pathogens in food, clinical and environmental samples, and the methodologies are generally known to one skilled in the art. It is generally recognized that the degree of sensitivity and specificity of probe hybridization is lower than that achieved through the previously described amplification techniques. The nucleic acid probes of the present invention can also possess a detectable label, such as a reporter-quencher combination as are employed in Scorpion probe assays or in 5′-exonuclease detection assays, such as the Taqman® assay.

The 3′ terminal nucleotide of the nucleic acid probe may be rendered incapable of extension by a nucleic acid polymerase in one embodiment of the invention. Such blocking may be carried out, for example by the attachment of a replication inhibitor moiety, such as a reporter or quencher, to the terminal 3′ carbon of the nucleic acid probe by a linking moiety, or by making the 3′-terminal nucleotide a dideoxynucleotide. Alternatively, the 3′ end of the nucleic acid probe may be rendered impervious to the 3′ to 5′ extension activity of a polymerase by incorporating one or more modified internucleotide linkages onto the 3′ end of the oligonucleotide. Minimally, the 3′ terminal internucleotide linkage must be modified, however, additional internucleotide linkages may be modified. Internucleotide modifications which prevent elongation from the 3′ end of the nucleic acid probe and/or which block the 3′ to 5′ exonuclease activity of the DNA polymerase during PCR may include phosphorothioate linkages, methylphosphonate linkages, boranophosphate linkages, and other similar polymerase-resistant internucleotide linkages. An alternative method to block 3′ extension of the probe is to form an adduct at the 3′ end of the probe using mitomycin C or other like antitumor antibiotics such as described in Basu et al., Biochemistry 32:4708-4718, 1993. Thus, the precise mechanism by which the 3′ end of the nucleic acid probe is protected from cleavage is not essential so long as the quencher is not cleaved from the nucleic acid probe.

A nucleic acid probe sequence can also optionally be employed with the primer sequence pairs of the present invention in an amplification based detection technique, such as in the 3′-exonuclease assay. Preferred primer/probe combinations are indicated in Table 1.

In some embodiments a corresponding primer and probe are used together in a primer-probe complex. In such embodiments, the 3′ terminus of the probe is typically attached to the 5′ terminus of the primer. These primer probe complexes of the instant invention can contain a non-amplifiable linker that connects the 3′ terminus of the probe region to the 5′ terminus of the primer region. This non-amplifiable linker stops extension of a complementary strand from proceeding into the probe region of the primer-probe complex. Examples of such non-amplifiable linkages include hexethylene glycol (HEG) and, preferably, 18-carbon linkers. Primer-probe complexes of the present invention can also contain a self-complementary region that allows the primer-probe complex to form a stem-loop structure when the probe is unbound from its target DNA, which may be useful, for example, in bringing the reporter and quencher into sufficiently close proximity to one another to cause the reporter signal to be quenched. In some instances, a quencher oligonucleotide can be employed with a primer-probe complex, which quencher oligonucleotide is capable of hybridizing to the probe region of the primer-probe complex when the probe region is unbound from its target DNA. If the reporter is attached to the primer-probe complex and the quencher is attached to the blocking oligonucleotide, this can bring the reporter and quencher into sufficiently close proximity to one another to allow quenching to occur. Examples of corresponding primers, probes, and quenchers are provided in Table 1.

Assay Methods

Detection of the selected gene targets and/or the genomic DNA regions identified by SEQ ID NOs: 686-696, and subsequent detection of the presence of STEC bacteria in a sample, may be accomplished in any suitable manner. Preferred methods are primer-directed amplification methods and nucleic acid hybridization methods. These methods may be used to detect STEC bacteria in a sample that is either a complex matrix or a purified culture, e.g., from an animal, environmental, or food source suspected of contamination.

A preferred embodiment of the instant invention comprises (1) culturing a complex sample mixture in a non-selective growth media to resuscitate the target bacteria, (2) releasing total target bacterial DNA, and (3) subjecting the total DNA to an amplification protocol with a primer pair of the invention and optionally with a nucleic acid probe comprising a detectable label.

Primer-Directed Amplification Assay Methods

A variety of primer-directed nucleic acid amplification methods are known in the art which can be employed in the present invention, including thermal cycling methods (e.g., PCR, RT-PCR, and LCR), as well as isothermal methods and strand displacement amplification (SDA). The preferred method is PCR. In one preferred embodiment, the corresponding forward and reverse primer pairs listed in Table 1 may be used as primers for use in primer-directed nucleic acid amplification for the detection of the target genes of interest and/or SEQ ID NOs: 686-696, and, ultimately, the detection and identification of STEC bacteria.

Sample Preparation:

The oligonucleotides and methods according to the instant invention may be used directly with any suitable clinical or environmental samples, without any need for sample preparation. In order to achieve higher sensitivity, and in situations where time is not a limiting factor, it is preferred that the samples be pre-treated and that pre-amplification enrichment is performed.

The minimum industry standard for the detection of food-borne bacterial pathogens is a method that will reliably detect the presence of one pathogen cell in 25 g of food matrix as described in Andrews et al., 1984, “Food Sample and Preparation of Sample Homogenate”, Chapter 1 in Bacteriological Analytical Manual, 8th Edition, Revision A, Association of Official Analytical Chemists, Arlington, Va. In order to satisfy this stringent criterion, enrichment methods and media have been developed to enhance the growth of the target pathogen cell in order to facilitate its detection by biochemical, immunological or nucleic acid hybridization means. Typical enrichment procedures employ media that will enhance the growth and health of the target bacteria and also inhibit the growth of any background or non-target microorganisms present. For example, the USDA has set forth a protocol for enrichment of samples of ground beef to be tested for pathogenic E. coli (U.S. Food and Drug Administration, Bacterial Analytical Manual).

Selective media have been developed for a variety of bacterial pathogens and one of skill in the art will know to select a medium appropriate for the particular organism to be enriched. A general discussion and recipes of non-selective media are described in the FDA Bacteriological Analytical Manual. (1998) published and distributed by the Association of Analytical Chemists, Suite 400, 2200 Wilson Blvd, Arlington, Va. 22201-3301.

After selective growth, a sample of the complex mixtures is removed for further analysis. This sampling procedure may be accomplished by a variety of means well known to those skilled in the art. In a preferred embodiment, 5 μl of the enrichment culture is removed and added to 200 μl of lysis solution containing protease. The lysis solution is heated at 37° C. for 20 min followed by protease inactivation at 95° C. for 10 min as described in the BAX® System User's Guide, DuPont Qualicon, Inc., Wilmington, Del.

PCR Assay Methods:

A preferred method for detecting the presence of the present invention's gene targets and subsequently STEC bacteria in a sample comprises (a) performing PCR amplification of two or more of SEQ ID NOs: 686-696 using primer pairs listed in Table 1 to produce a PCR amplification result; and (b) detecting the amplification, whereby a positive detection of the amplification indicates the presence of STEC bacteria in the sample.

In another preferred embodiment, prior to performing PCR amplification, a step of preparing the sample may be carried out. The preparing step may comprise at least one of the following processes: (1) bacterial enrichment, (2) separation of bacterial cells from the sample, (3) cell lysis, and (4) total DNA extraction.

Amplification Conditions:

A skilled person will understand that any generally acceptable PCR conditions may be used for successfully detecting the gene targets and the target STEC bacteria using the oligonucleotides of the instant invention, and depending on the sample to be tested and other laboratory conditions, routine optimization for the PCR conditions may be necessary to achieve optimal sensitivity and specificity. Optimally, they achieve PCR amplification results from all of the intended specific targets while giving no PCR results for other, non-target species.

Detection/Examination/Analysis:

Primer-directed amplification products of SEQ ID NOs: 686-696 can be analyzed using various methods. Homogenous detection refers to a preferred method for the detection of amplification products where no separation (such as by gel electrophoresis) of amplification products from template or primers is necessary. Homogeneous detection is typically accomplished by measuring the level of fluorescence of the reaction mixture during or immediately following amplification. In addition, heterogeneous detection methods, which involve separation of amplification products during or prior to detection, can be employed in the present invention.

Homogenous detection may be employed to carry out “real-time” primer-directed nucleic acid amplification and detection, using primer pairs of the instant invention (e.g., “real-time” PCR and “real-time” RT-PCR). Preferred “real-time” methods are set forth in U.S. Pat. Nos. 6,171,785, 5,994,056, 6,326,145, 5,804,375, 5,538,848, 5,487,972, and 5,210,015, each of which is hereby incorporated by reference in its entirety.

A particularly preferred “real-time” detection method is the Scorpion probe assay as set forth in U.S. Pat. No. 6,326,145, which is hereby incorporated by reference in its entirety. In the Scorpion probe assay, PCR amplification is performed using a Scorpion probe (either unimolecular or bimolecular) as a primer-probe complex, the Scorpion probe possessing an appropriate reporter-quencher pair to allow the detectable signal of the reporter to be quenched prior to elongation of the primer. Post-elongation, the quenching effect is eliminated and the amount of signal present is quantitated. As the amount of amplification product increases, an equivalent increase in detectable signal will be observed, thus allowing the amount of amplification product present to be determined as a function of the amount of detectable signal measured. When more than one Scorpion probe is employed in a Scorpion probe assay of present invention, each probe can have a different detectable label (e.g., reporter-quencher pair) attached, thus allowing each probe to be detected independently of the other probes.

In a certain embodiment, amplification and detection of two or more of SEQ ID NOs: 686-696 is performed using differentially labeled Scorpion probes. Examples of primers and probes, including the target sequences to which they are directed, are provided in Table 1. Additional specific examples of primers, probes, and quenchers which can be employed alone or in combination for detection of STEC bacteria are provided in Tables 2, 3, and 8.

Another preferred “real-time” detection method is the 5′-exonuclease detection method, as set forth in U.S. Pat. Nos. 5,804,375, 5,538,848, 5,487,972, and 5,210,015, each of which is hereby incorporated by reference in its entirety. In the 5′-exonuclease detection assay a modified probe is employed during PCR which binds intermediate to or between the two members of the amplification primer pair. The modified probe possesses a reporter and a quencher and is designed to generate a detectable signal to indicate that it has hybridized with the target nucleic acid sequence during PCR. As long as both the reporter and the quencher are on the probe, the quencher stops the reporter from emitting a detectable signal. However, as the polymerase extends the primer during amplification, the intrinsic 5′ to 3′ nuclease activity of the polymerase degrades the probe, separating the reporter from the quencher, and enabling the detectable signal to be emitted. Generally, the amount of detectable signal generated during the amplification cycle is proportional to the amount of product generated in each cycle.

It is well known that the efficiency of quenching is a strong function of the proximity of the reporter and the quencher, i.e., as the two molecules get closer, the quenching efficiency increases. As quenching is strongly dependent on the physical proximity of the reporter and quencher, the reporter and the quencher are preferably attached to the probe within a few nucleotides of one another, usually within 30 nucleotides of one another, more preferably with a separation of from about 6 to 16 nucleotides. Typically, this separation is achieved by attaching one member of a reporter-quencher pair to the 5′ end of the probe and the other member to a nucleotide about 6 to 16 nucleotides away.

Again, when more than one Taqman® probe is employed in a 5′-exonuclease detection assay of present invention, such as one directed to two or more of SEQ ID NOs: 686-696, each probe can have a different detectable label (e.g., reporter-quencher pair) attached, thus allowing each probe to be detected independently of the other probes.

Another preferred method of homogenous detection involves the use of DNA melting curve analysis, particularly with the BAX® System hardware and reagent tablets from DuPont Qualicon Inc. The details of the system are given in U.S. Pat. No. 6,312,930 and PCT Publication Nos. WO 97/11197 and WO 00/66777, each of which is hereby incorporated by reference in its entirety.

Melting curve analysis detects and quantifies double stranded nucleic acid molecule (“dsDNA” or “target”) by monitoring the fluorescence of the target amplification product (“target amplicon”) during each amplification cycle at selected time points.

As is well known to the skilled artisan, the two strands of a dsDNA separate or melt, when the temperature is higher than its melting temperature. Melting of a dsDNA molecule is a process, and under a given solution condition, melting starts at a temperature (designated T_(MS) hereinafter), and completes at another temperature (designated T_(ME) hereinafter). The familiar term, T_(m), designates the temperature at which melting is 50% complete.

A typical PCR cycle involves a denaturing phase where the target dsDNA is melted, a primer annealing phase where the temperature optimal for the primers to bind to the now-single-stranded target, and a chain elongation phase (at a temperature T_(E)) where the temperature is optimal for DNA polymerase to function.

According to the present invention, T_(MS) should be higher than T_(E), and T_(ME) should be lower (often substantially lower) than the temperature at which the DNA polymerase is heat-inactivated. Melting characteristics are effected by the intrinsic properties of a given dsDNA molecule, such as deoxynucleotide composition and the length of the dsDNA.

Intercalating dyes will bind to double stranded DNA. The dye/dsDNA complex will fluoresce when exposed to the appropriate excitation wavelength of light, which is dye dependent, and the intensity of the fluorescence may be proportionate to concentration of the dsDNA. Methods taking advantage of the use of DNA intercalating dyes to detect and quantify dsDNA are known in the art. Many dyes are known and used in the art for these purposes. The instant methods also take advantage of such relationship.

Examples of such intercalating dyes include, but are not limited to, SYBR Green-I®, ethidium bromide, propidium iodide, TOTO®-1 {Quinolinium, 1-1′-[1,3-propanediylbis[(dimethyliminio)-3,1-propanediyl]]bis[4-[(3-methyl-2(3H)-benzothiazolylidene)methyl]]-, tetraiodide}, and YoPro® {Quinolinium, 4-[(3-methyl-2(3H)-benzoxazolylidene)methyl]-1-[3-(trimethylammonio)-propyl]-,diiodide}. Most preferred for the instant invention is a non-asymmetrical cyanide dye such as SYBR Green-I®, manufactured by Molecular Probes, Inc. (Eugene, Oreg.).

Melting curve analysis is achieved by monitoring the change in fluorescence while the temperature is increased. When the temperature reaches the T_(MS) specific for the target amplicon, the dsDNA begins to denature. When the dsDNA denatures, the intercalating dye dissociates from the DNA and fluorescence decreases. Mathematical analysis of the negative of the change of the log of fluorescence divided by the change in temperature plotted against the temperature results in the graphical peak known as a melting curve.

It should be understood that the present invention could be operated using a combination of these techniques, such as by having a Scorpion probe directed to one target region and a Taqman® probe directed to a second target region. It should also be understood that the invention is not limited to the above described techniques. Rather, one skilled in the art would recognize that other techniques for detecting amplification as known in the art may also be used. For example, techniques such as PCR-based quantitative sequence detection (QSD) may be performed using nucleic acid probes which, when present in the single-stranded state in solution, are configured such that the reporter and quencher are sufficiently close to substantially quench the reporter's emission. However, upon hybridization of the intact reporter-quencher nucleic acid probe with the amplified target nucleic acid sequence, the reporter and quenchers become sufficiently distant from each other. As a result, the quenching is substantially abated causing an increase in the fluorescence emission detected.

In addition to homogenous detection methods, a variety of other heterogeneous detection methods are known in the art which can be employed in the present invention, including standard non-denaturing gel electrophoresis (e.g., acrylamide or agarose), denaturing gradient gel electrophoresis, and temperature gradient gel electrophoresis. Standard non-denaturing gel electrophoresis is a simple and quick method of PCR detection, but may not be suitable for all applications.

Denaturing Gradient Gel Electrophoresis (DGGE) is a separation method that detects differences in the denaturing behavior of small DNA fragments (200-700 bp). The principle of the separation is based on both fragment length and nucleotide sequence. In fragments that are the same length, a difference as little as one base pair can be detected. This is in contrast to non-denaturing gel electrophoresis, where DNA fragments are separated only by size. This limitation of non-denaturing gel electrophoresis results because the difference in charge density between DNA molecules is near neutral and plays little role in their separation. As the size of the DNA fragment increases, its velocity through the gel decreases.

DGGE is primarily used to separate DNA fragments of the same size based on their denaturing profiles and sequence. Using DGGE, two strands of a DNA molecule separate, or melt, when heat or a chemical denaturant is applied. The denaturation of a DNA duplex is influenced by two factors: 1) the hydrogen bonds formed between complimentary base pairs (since GC rich regions melt at higher denaturing conditions than regions that are AT rich); and 2) the attraction between neighboring bases of the same strand, or “stacking.” Consequently, a DNA molecule may have several melting domains with each of their individual characteristic denaturing conditions determined by their nucleotide sequence. DGGE exploits the fact that otherwise identical DNA molecules having the same length and DNA sequence, with the exception of only one nucleotide within a specific denaturing domain, will denature at different temperatures or Tm. Thus, when the double-stranded (ds) DNA fragment is electrophoresed through a gradient of increasing chemical denaturant it begins to denature and undergoes both a conformational and mobility change. The dsDNA fragment will travel faster than a denatured single-stranded (ss) DNA fragment, since the branched structure of the single-stranded moiety of the molecule becomes entangled in the gel matrix. As the denaturing environment increases, the dsDNA fragment will completely dissociate and mobility of the molecule through the gel is retarded at the denaturant concentration at which the particular low denaturing domains of the DNA strand dissociate. In practice, the electrophoresis is conducted at a constant temperature (around 60° C.) and chemical denaturants are used at concentrations that will result in 100% of the DNA molecules being denatured (i.e., 40% formamide and 7M urea). This variable denaturing gradient is created using a gradient maker, such that the composition of each DGGE gel gradually changes from 0% denaturant up to 100% denaturant. Of course, gradients containing a reduced range of denaturant (e.g., 35% to 60%) may also be poured for increased separation of DNA.

The principle used in DGGE can also be applied to a second method that uses a temperature gradient instead of a chemical denaturant gradient. This method is known as Temperature Gradient Gel Electrophoresis (TGGE). This method makes use of a temperature gradient to induce the conformational change of dsDNA to ssDNA to separate fragments of equal size with different sequences. As in DGGE, DNA fragments with different nucleotide sequences will become immobile at different positions in the gel. Variations in primer design can be used to advantage in increasing the usefulness of DGGE for characterization and identification of the PCR products. These methods and principles of using primer design variations are described in PCR Technology Principles and Applications, Henry A. Erlich Ed., M. Stockton Press, NY, pages 71 to 88 (1988).

Instrumentation:

When homogenous detection is employed, the level of fluorescence is preferably measured using a laser fluorometer such as, for example, an ABI Prism Model 7500 Fast Sequence Detector. However, similar detection systems for measuring the level of fluorescence in a sample are included in the invention.

Reagents and Kits:

Any suitable nucleic acid replication composition (“replication composition”) in any format can be used. A typical replication composition for PCR amplification may comprise, for example, dATP, dCTP, dGTP, dTTP, target specific primers and a suitable polymerase.

If the replication composition is in liquid form, suitable buffers known in the art may be used (Sambrook, J. et al., supra).

Alternatively, if the replication composition is contained in a tablet form, then typical tabletization reagents may be included such as stabilizers and binding agents. Preferred tabletization technology is set forth in U.S. Pat. Nos. 4,762,857 and 4,678,812, each of which is hereby incorporated by reference in its entirety.

A preferred replication composition of the instant invention comprises (a) at least one primer pair selected from Table 1, and (b) thermostable DNA polymerase. Another preferred replication composition comprises (a) at least two primer pairs selected from Table 1, each directed toward a different target DNA region; and (b) thermostable DNA polymerase. In some embodiments, primer pairs directed to three or more of SEQ ID NOs: 686-696 are included. In further embodiments, primer pairs directed to four or more of SEQ ID NOs: 686-696 are included. In still further embodiments, primer pairs directed to five or more of SEQ ID NOs: 686-696 are included.

A more preferred replication composition of the present invention comprises (a) at least two primer pairs and any corresponding probe or blocking oligonucleotide selected from Table 1, wherein each nucleic acid probe or primer-probe complex employed comprises a detectable label; and (b) thermostable DNA polymerase. Preferably the detectable label comprises a reporter capable of emitting a detectable signal and a quencher capable of substantially quenching the reporter and preventing the emission of the detectable signal when the reporter and quencher are in sufficiently close proximity to one another.

A preferred kit of the instant invention comprises any one of the above replication compositions. A preferred tablet of the instant invention comprises any one of the above replication compositions. More preferably, a kit of the instant invention comprises the foregoing preferred tablet.

In some instances, an internal positive control can be included in the reaction. The internal positive control can include control template nucleic acids (e.g. DNA or RNA), control primers, and control nucleic acid probe. The advantages of an internal positive control contained within a PCR reaction have been previously described (U.S. Pat. No. 6,312,930 and PCT Application No. WO 97/11197, each of which is hereby incorporated by reference in its entirety), and include: (i) the control may be amplified using a single primer; (ii) the amount of the control amplification product is independent of any target DNA or RNA contained in the sample; (iii) the control DNA can be tableted with other amplification reagents for ease of use and high degree of reproducibility in both manual and automated test procedures; (iv) the control can be used with homogeneous detection, i.e., without separation of product DNA from reactants; and (v) the internal control has a melting profile that is distinct from other potential amplification products in the reaction and/or a detectable label on the control nucleic acid that is distinct from the detectable label on the nucleic acid probe directed to the target.

Control DNA will be of appropriate size and base composition to permit amplification in a primer-directed amplification reaction. The control template DNA sequence may be obtained from the E. coli genome, or from another source, but must be reproducibly amplified under the same conditions that permit the amplification of the target amplification product.

Preferred control sequences include, for example, control primers and probes directed toward SV40 DNA.

The control reaction is useful to validate the amplification reaction. Amplification of the control DNA occurs within the same reaction tube as the sample that is being tested, and therefore indicates a successful amplification reaction when samples are target negative, i.e. no target amplification product is produced. In order to achieve significant validation of the amplification reaction, a suitable number of copies of the control DNA template must be included in each amplification reaction.

In some instances it may be useful to include an additional negative control replication composition. The negative control replication composition will contain the same reagents as the replication composition but without the polymerase. The primary function of such a control is to monitor spurious background fluorescence in a homogeneous format when the method employs a fluorescent means of detection.

Replication compositions may be modified depending on whether they are designed to be used to amplify target DNA or the control DNA. Replication compositions that will amplify the target DNA (test replication compositions) may include (i) a polymerase (generally thermostable), (ii) a primer pair capable of hybridizing to the target DNA and (iii) necessary buffers for the amplification reaction to proceed. Replication compositions that will amplify the control DNA (positive control, or positive replication composition) may include (i) a polymerase (generally thermostable) (ii) the control DNA; (iii) at least one primer capable of hybridizing to the control DNA; and (iv) necessary buffers for the amplification reaction to proceed. In addition, the replication composition for either target DNA or control DNA amplification can contain a nucleic acid probe, preferably possessing a detectable label.

Nucleic Acid Hybridization Methods

In addition to primer-directed amplification assay methods, nucleic acid hybridization assay methods can be employed in the present invention for detection of STEC bacteria. The basic components of a nucleic acid hybridization test include a probe, a sample suspected of containing STEC bacteria, and a specific hybridization method. Typically the probe length can vary from as few as 5 bases to the full length of the diagnostic sequence and will depend upon the specific test to be done. Only part of the probe molecule need be complementary to the nucleic acid sequence to be detected. In addition, the complementarity between the probe and the target sequence need not be perfect. Hybridization does occur between imperfectly complementary molecules with the result that a certain fraction of the bases in the hybridized region are not paired with the proper complementary base.

Probes particularly useful in nucleic acid hybridization methods are any of SEQ ID NOs: 1-696, or sequences derived therefrom.

The sample may or may not contain STEC bacteria. The sample may take a variety of forms, however will generally be extracted from an animal, environmental or food source suspected of contamination. The DNA may be detected directly but most preferably, the sample nucleic acid must be made available to contact the probe before any hybridization of probe and target molecule can occur. Thus the organism's DNA is preferably free from the cell and placed under the proper conditions before hybridization can occur. Methods of in-solution hybridization necessitate the purification of the DNA in order to be able to obtain hybridization of the sample DNA with the probe. This has meant that utilization of the in-solution method for detection of target sequences in a sample requires that the nucleic acids of the sample must first be purified to eliminate protein, lipids, and other cell components, and then contacted with the probe under hybridization conditions. Methods for the purification of the sample nucleic acid are common and well known in the art (Sambrook et al., supra).

In one preferred embodiment, hybridization assays may be conducted directly on cell lysates, without the need to extract the nucleic acids. This eliminates several steps from the sample-handling process and speeds up the assay. To perform such assays on crude cell lysates, a chaotropic agent is typically added to the cell lysates prepared as described above. The chaotropic agent stabilizes nucleic acids by inhibiting nuclease activity. Furthermore, the chaotropic agent allows sensitive and stringent hybridization of short oligonucleotide probes to DNA at room temperature (Van Ness and Chen, Nucl. Acids Res. 19:5143-5151 (1991)). Suitable chaotropic agents include guanidinium chloride, guanidinium thiocyanate, sodium thiocyanate, lithium tetrachloroacetate, sodium perchlorate, rubidium tetrachloroacetate, potassium iodide, and cesium trifluoroacetate, among others. Typically, the chaotropic agent will be present at a final concentration of about 3M. If desired, one can add formamide to the hybridization mixture, typically 30-50% (v/v).

Alternatively, one can purify the sample nucleic acids prior to probe hybridization. A variety of methods are known to one of skill in the art (e.g., phenol-chloroform extraction, Isoquick extraction (MicroProbe Corp., Bothell, Wash.), and others). Pre-hybridization purification is particularly useful for standard filter hybridization assays. Furthermore, purification facilitates measures to increase the assay sensitivity by incorporating in vitro RNA amplification methods such as self-sustained sequence replication (see for example Fahy et al., In PCR Methods and Applications, Cold Spring Harbor Laboratory: Cold Spring Harbor, N.Y. (1991), pp. 25-33) or reverse transcriptase PCR (Kawasaki, In PCR Protocols: A Guide to Methods and Applications, M. A. Innis et al., Eds., (1990), pp. 21-27).

Once the DNA is released, it can be detected by any of a variety of methods. However, the most useful embodiments have at least some characteristics of speed, convenience, sensitivity, and specificity.

Hybridization methods are well known in the art. Typically the probe and sample must be mixed under conditions which will permit nucleic acid hybridization. This involves contacting the probe and sample in the presence of an inorganic or organic salt under the proper concentration and temperature conditions. The probe and sample nucleic acids must be in contact for a long enough time that any possible hybridization between the probe and sample nucleic acid may occur. The concentration of probe or target in the mixture will determine the time necessary for hybridization to occur. The higher the probe or target concentration, the shorter the hybridization incubation time needed.

Various hybridization solutions can be employed. Typically, these comprise from about 20 to 60% volume, preferably 30%, of a polar organic solvent. A common hybridization solution employs about 30-50% v/v formamide, about 0.15 to 1M sodium chloride, about 0.05 to 0.1 M buffers, such as sodium citrate, Tris-HCl, PIPES or HEPES (pH range about 6-9), about 0.05 to 0.2% detergent, such as sodium dodecylsulfate, or between 0.5-20 mM EDTA, FICOLL (Pharmacia Inc.) (about 300-500 kilodaltons), polyvinylpyrrolidone (about 250-500 kdal), and serum albumin. Also included in the typical hybridization solution will be unlabeled carrier nucleic acids from about 0.1 to 5 mg/mL, fragmented nucleic DNA (e.g., calf thymus or salmon sperm DNA, or yeast RNA), and optionally from about 0.5 to 2% wt/vol glycine. Other additives may also be included, such as volume exclusion agents which include a variety of polar water-soluble or swellable agents (e.g., polyethylene glycol), anionic polymers (e.g., polyacrylate or polymethylacrylate), and anionic saccharidic polymers (e.g., dextran sulfate).

Nucleic acid hybridization is adaptable to a variety of assay formats. One of the most suitable is the sandwich assay format. The sandwich assay is particularly adaptable to hybridization under non-denaturing conditions. A primary component of a sandwich-type assay is a solid support. The solid support has adsorbed to it or covalently coupled to it immobilized nucleic acid probe that is unlabeled and complementary to one portion of the DNA sequence.

The sandwich assay may be encompassed in an assay kit. This kit would include a first component for the collection of samples suspected of contamination and buffers for the disbursement and lysis of the sample. A second component would include media in either dry or liquid form for the hybridization of target and probe polynucleotides, as well as for the removal of undesirable and nonduplexed forms by washing. A third component includes a solid support (dipstick) upon which is fixed (or to which is conjugated) unlabeled nucleic acid probe(s) that is (are) complementary to one or more targets of interest, for instance one or more of SEQ ID NOs: 686-696. A fourth component would contain labeled probe that is complementary to a second and different region of the same DNA strand to which the immobilized, unlabeled nucleic acid probe of the third component is hybridized.

In a preferred embodiment, SEQ ID NOs: 1-685 or derivations thereof may be used as 3′ blocked detection probes in either a homogeneous or heterogeneous assay format. For example, a probe generated from these sequences may be 3′ blocked or non-participatory and will not be extended by, or participate in, a nucleic acid amplification reaction. Additionally, the probe incorporates a label that can serve as a reactive ligand that acts as a point of attachment for the immobilization of the probe/analyte hybrid or as a reporter to produce detectable signal. Accordingly, genomic or cDNA isolated from a sample suspected of E. coli contamination is amplified by standard primer-directed amplification protocols in the presence of an excess of the 3′ blocked detection probe to produce amplification products. Because the probe is 3′ blocked, it does not participate or interfere with the amplification of the target. After the final amplification cycle, the detection probe anneals to the relevant portion of the amplified DNA and the annealed complex is then captured on a support through the reactive ligand.

In some instances it is desirable to incorporate a ligand labeled dNTP, with the label probe in the replication composition to facilitate immobilization of the PCR reaction product on a support and then detection of the immobilized product by means of the labeled probe reagent. For example a biotin, digoxigenin, or digoxin labeled dNTP could be added to PCR reaction composition. The biotin, digoxigenin, or digoxin incorporated in the PCR product could then be immobilized respectively on to a strepavidin, anti-digoxin or antidigoxigenin antibody support. The immobilized PCR product could then be detected by the presence of the probe label.

EXAMPLES

The present invention is further defined in the following Examples. It should be understood that these Examples, while indicating preferred embodiments of the invention, are given by way of illustration only.

Example 1 Determination of Inclusivity/Exclusivity of the Stx, Eae, O157, O45, O103, and O145 Primers and Probes

Samples of organisms were analyzed to establish inclusivity and exclusivity of Scorpion® probes of the present invention directed toward stx1/2, eae, O157, O45, O103, and O145 targets. For inclusivity, independent, bona fide STEC isolates appropriate for each assay (O157:H7, O45, O103 and O145, and various other organisms containing stx₁, stx₂, and eae) were used. For exclusivity, closely related non-target organisms, including other STEC organisms that were not targets of the assays, were used to ensure that the assay would discriminate the target organisms from other non-target organisms.

DNA Lysate Preparation

Material tested was overnight growth pure cultures of the target and non-target organisms grown at 37° C. in BHI media. Pure cultures were grown overnight to cell densities of approximately 1×10⁹ cfu/ml. For exclusivity, non-diluted overnight cultures were tested. For inclusivity, overnight cultures were diluted approximately 1:10,000 into TSB. 20 μl of the material to be tested was added to 200 μl of BAX® lysis reagent (DuPont Qualicon, Wilmington, Del.). The mixture was incubated at 37° C. for 20 minutes, then further incubated at 95° C. for 10 minutes, and finally cooled to 5° C.

PCR Conditions

5-30 μl of the DNA lysate was used to hydrate lyophylized PCR reaction components to obtain DNA lysate/PCR reaction component mixtures. The PCR reaction components included lyophilized reagent tablets containing APTATaq DNA Polymerase (Roche, Mannheim, Germany), deoxynucleotides (Roche Diagnostics, Indianapolis, Ind.), BSA, surfactamps (Sigma-Aldrich, St. Louis, Mo.), and positive control DNA. In addition, the primers, quenchers, and Scorpions® listed in Tables 2 and 3 were included in the amounts provided. For the Scorpion® probes, the 5′ end label and linker are also provided in Tables 2 and 3. Each of these Scorpion® probes was designed as a bi-molecular Scorpion®, such that its structure includes (in 5′ to 3′ order) a 5′ fluorescent end label, a probe sequence, an 18-carbon non-amplifiable linker, and a primer sequence. Tables 2 and 3 also list the quenching label that was attached to the 3′ terminus of the corresponding quencher oligonucleotides.

TABLE 2 Nucleic acid primers, probes, and quenchers used for inclusivity and exclusivity testing For Scorpions Probe SEQ Primer Internal SEQ Nucleotide Amt. Per ID End SEQ Label/ ID Name Target Reaction NO: Label ID NO: Linker NO: Scorpion O45   20-250 Cal 415 18- 431 O45A-807B nM Fluor Carbon Red Spacer 610 Forward primer O45  100-500 423 O45A807-24 nM Quencher O45  100-1300 447 BHQ2 O45A-807B nM Reverse Primer O45  100-250 472 O45Arc901-24 nM Scorpion O103  20-250 Cal 490 18- 505 O103A-rc851 nM Fluor Carbon Gold Spacer 540 Forward Primer O103 100-500 490 O103Arc851-22 nM Quencher O103 100-1300 520 BHQ1 O103A-rc851 nM Reverse Primer O103 100-250 547 O103A707-24 nM Scorpion O145  20-250 Quasar 565 18- 580 O145A-rc713 nM 670 Carbon Spacer Forward Primer O145 100-500 565 O145Arc713-22 nM Quencher O145 100-1300 595 BHQ2 O145A-rc713 nM Reverse Primer O145 100-250 610 O145A620-22 nM Scorpion Pos.  10-100 Tamra 697 BHQ2/ 699 (Unimolecular) Control nM 18- SV40 scorpion 1 Carbon Linker Forward Primer Pos.  25-150 698 SV4312 Control nM Reverse Primer Pos. 100-400 700 SV4222 Control nM

TABLE 3 Nucleic acid primers, probes, and quenchers used for inclusivity and exclusivity testing For Scorpions Probe SEQ Primer Internal SEQ Amt. Per ID End SEQ Label/ ID Nucleotide Name Target reaction NO: Label ID NO: Linker NO: Scorpion O157i- O157 20-250 Cal 625 18- 641 rc478 nM Fluor Carbon Gold Spacer 540 Quencher #3 O157i O157 100-1300 661 BHQ1 rc478 nM Forward Primer O157 100-500  625 O157irc478-26 nM Reverse Primer O157 100-500  678 O157i346-23 nM Scorpion Stx1A- Stx1A 20-250 Cal 8 18- 23 rc203B nM Fluor Carbon Red Spacer 610 Quencher Stx1A- Stx1A 100-1300 38 BHQ2 rc203B nM Forward Primer Stx1A 100-500  8 Stx1A-rc203 nM Reverse Primer Stx1A 100-500  65 Stx1A114-27 nM Scorpion stx2A-rc650 Stx2A 20-250 Cal 81 18- 96 nM Fluor Carbon Red Spacer 610 Quencher stx2A- Stx2A 100-1300 112 BHQ2 rc650 nM Forward Primer Stx2A 100-500  81 stx2Arc650-24 nM Reverse Primer Stx2A 100-500  135 Stx2A594-26 nM Scorpion EAE-rc745 EAE 20-250 Quasar 152 18- 167 nM 670 Carbon Spacer Quencher EAE-rc745 EAE 100-1300 183 BHQ2 nM Forward Primer EAE 100-500  152 EAErc745-24 nM Reverse Primer EAE 100-500  198 EAE685-29 nM Scorpion Pos . 10-100 Tamra 697 BHQ2/ 699 (Unimolecular) SV40 Control nM 18- scorpion 1 Carbon Linker Forward Primer Pos. 25-150 698 SV4312 Control nM Reverse Primer Pos. 100-400  700 SV4222 Control nM

Amplification and testing were performed on the BAX® Q7 instrument (DuPont Qualicon, Wilmington, Del.). The thermal cycling conditions were as follows: 2 minutes at 94° C., followed by 43 cycles of 94° C. for 10 seconds and 63° C. for 40 seconds, with the fluorescent signal captured during the 63° C. step at each cycle.

Results

As can be seen in Tables 4 through 7, the individual Scorpion® probes were each able to distinguish the various targets from non-targets.

TABLE 4 O45, O103, and O145 inclusivity Sample O- BAX ® System Result ID Source Type O45 O103 O145 R62 MSU O45 Positive Negative Negative R63 MSU O45 Positive Negative Negative R64 MSU O45 Positive Negative Negative R66 MSU O103 Negative Positive Negative R67 MSU O103 Negative Positive Negative R68 MSU O103 Negative Positive Negative R77 MSU O145 Negative Negative Positive R78 MSU O145 Negative Negative Positive R79 MSU O145 Negative Negative Positive R80 MSU O145 Negative Negative Positive R163 USDA- O103 Negative Positive Negative MARC R164 USDA- O103 Negative Positive Negative MARC R165 USDA- O103 Negative Positive Negative MARC R166 USDA- O103 Negative Positive Negative MARC R167 USDA- O103 Negative Positive Negative MARC R168 USDA- O103 Negative Positive Negative MARC R198 USDA- O145 Negative Negative Positive MARC DD2439 DuPont O145 Negative Negative Positive DD2450 DuPont O45 Positive Negative Negative DD2483 DuPont O145 Negative Negative Positive DD2521 DuPont O103 Negative Positive Negative DD2526 DuPont O145 Negative Negative Positive DD2530 DuPont O103 Negative Positive Negative DD13349 USDA-ARS O45 Positive Negative Negative DD13350 USDA-ARS O45 Positive Negative Negative DD13351 USDA-ARS O45 Positive Negative Negative DD13352 USDA-ARS O45 Positive Negative Negative DD13353 USDA-ARS O45 Positive Negative Negative DD13354 USDA-ARS O45 Positive Negative Negative DD13355 USDA-ARS O45 Positive Negative Negative DD13358 USDA-ARS O45 Positive Negative Negative DD13359 USDA-ARS O45 Positive Negative Negative DD13360 USDA-ARS O45 Positive Negative Negative DD13361 USDA-ARS O45 Positive Negative Negative DD13373 USDA-ARS O103 Negative Positive Negative DD13374 USDA-ARS O103 Negative Positive Negative DD13375 USDA-ARS O103 Negative Positive Negative DD13376 USDA-ARS O103 Negative Positive Negative DD13377 USDA-ARS O103 Negative Positive Negative DD13378 USDA-ARS O103 Negative Positive Negative DD13379 USDA-ARS O103 Negative Positive Negative DD13380 USDA-ARS O103 Negative Positive Negative DD13381 USDA-ARS O103 Negative Positive Negative DD13382 USDA-ARS O103 Negative Positive Negative DD13383 USDA-ARS O103 Negative Positive Negative DD13384 USDA-ARS O103 Negative Positive Negative DD13385 USDA-ARS O103 Negative Positive Negative DD13386 USDA-ARS O103 Negative Positive Negative DD13387 USDA-ARS O103 Negative Positive Negative DD13388 USDA-ARS O103 Negative Positive Negative DD13389 USDA-ARS O103 Negative Positive Negative DD13390 USDA-ARS O145 Negative Negative Positive DD13391 USDA-ARS O145 Negative Negative Positive DD13392 USDA-ARS O145 Negative Negative Positive DD13393 USDA-ARS O145 Negative Negative Positive DD13394 USDA-ARS O145 Negative Negative Positive DD13395 USDA-ARS O145 Negative Negative Positive DD13397 USDA-ARS O145 Negative Negative Positive DD13398 USDA-ARS O145 Negative Negative Positive

TABLE 5 O157:H7, stx, and eae inclusivity Sample BAX ® System Result ID Source O-Type stx₁ and/or stx₂ eae TD8136 DuPont O157:H7 Positive Positive MA6 DuPont O157:H7 Positive Positive 493/89 DuPont O157:H7 Positive Positive R81 MDP04- O-:H52 Positive Positive 01392 R88 MDP06- O141:H38 Positive Positive 00245 DD1450 DuPont O157:H7 Positive Positive DD2530 DuPont O103:H2 Positive Positive DD12787 DuPont O157:H7 Negative Positive DD13040 DuPont O157:H7 Negative Positive DD13469 DuPont O157:H7 Positive Positive DD640 DuPont O157:H7 Positive Positive DD642 DuPont O157:H7 Positive Positive DD1385 DuPont O157:H7 Positive Positive DD12797 DuPont O157:H7 Positive Positive DD1452 DuPont O157:H7 Positive Positive DD1460 DuPont O157:H7 Positive Positive DD1461 DuPont O157:H7 Positive Positive DD1972 DuPont O157:H7 Positive Positive DD1976 DuPont O157:H7 Positive Positive DD1977 DuPont O157:H7 Positive Positive DD1979 DuPont O157:H7 Positive Positive DD1982 DuPont O157:H7 Positive Positive DD1987 DuPont O157:H7 Positive Positive DD1988 DuPont O157:H7 Positive Positive DD1989 DuPont O157:H7 Positive Positive DD1991 DuPont O157:H7 Positive Positive DD5896 DuPont O157:H7 Positive Positive DD7101 DuPont O157:H7 Positive Positive DD8295 DuPont O157:H7 Positive Positive DD8300 DuPont O157:H7 Positive Positive DD8856 DuPont O157:H7 Positive Positive DD8865 DuPont O157:H7 Positive Positive DD8872 DuPont O157:H7 Positive Positive DD8873 DuPont O157:H7 Positive Positive DD10133 DuPont O157:H7 Positive Positive DD10901 DuPont O157:H7 Positive Positive DD10911 DuPont O157:H7 Positive Positive DD12817 DuPont O157:H7 Positive Positive DD12901 DuPont O157:H7 Positive Positive DD13038 DuPont O157:H7 Positive Positive DD10920 DuPont O157:H7 Positive Positive DD10921 DuPont O157:H7 Positive Positive DD12807 DuPont O157:H7 Positive Positive DD13054 DuPont O157:H7 Positive Positive DD13055 DuPont O157:H7 Positive Positive DD13072 DuPont O157:H7 Positive Positive DD13077 DuPont O157:H7 Positive Positive DD13078 DuPont O157:H7 Positive Positive DD13174 DuPont O157:H7 Positive Positive DD13175 DuPont O157:H7 Positive Positive DD13176 DuPont O157:H7 Positive Positive DD13182 DuPont O157:H7 Positive Positive DD13189 DuPont O157:H7 Positive Positive DD13190 DuPont O157:H7 Positive Positive DD13196 DuPont O157:H7 Positive Positive DD13197 DuPont O157:H7 Positive Positive DD13199 DuPont O157:H7 Positive Positive DD13241 DuPont O157:H7 Positive Positive DD13262 DuPont O157:H7 Positive Positive

TABLE 6 Non-E. coli exclusivity BAX ® System Result stx₁ Sample ID Source Organism O45 O103 O145 and/or stx₂ eae O157: H7 DD373 DuPont Klebsiella Neg. Neg. Neg. Neg. Neg. Neg. pneumoniae DD374 DuPont Proteus Neg. Neg. Neg. Neg. Neg. Neg. mirabilis DD383 DuPont Citrobacter Neg. Neg. Neg. Neg. Neg. Neg. freundii DD657 DuPont Klebsiella Neg. Neg. Neg. Neg. Neg. Neg. ozaenae DD658 DuPont Klebsiella Neg. Neg. Neg. Neg. Neg. Neg. oxytoca DD2389 DuPont Hafnia alvei Neg. Neg. Neg. Neg. Neg. Neg. DD2417 DuPont Serratia Neg. Neg. Neg. Neg. Neg. Neg. liquefaciens DD2558 DuPont Citrobacter Neg. Neg. Neg. Neg. Neg. Neg. freundii DD3064 DuPont Morganella Neg. Neg. Neg. Neg. Neg. Neg. morganii DD3982 DuPont Pseudomonas Neg. Neg. Neg. Neg. Neg. Neg. aeruginosa DD5588 DuPont Hafnia alvei Neg. Neg. Neg. Neg. Neg. Neg. DD6121 DuPont Gram negative Neg. Neg. Neg. Neg. Neg. Neg. rod DD7083 DuPont Unknown Neg. Neg. Neg. Neg. Neg. Neg. DD13142 DuPont Morganella Neg. Neg. Neg. Neg. Neg. Neg. morganii DD13147 DuPont Providencia Neg. Neg. Neg. Neg. Neg. Neg. rettgeri DD13148 DuPont Pseudomonas Neg. Neg. Neg. Neg. Neg. Neg. aeruginosa DD13186 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. amnigenus DD13187 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. amnigenus DD13094 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. sakazakii DD13099 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. sakazakii DD13134 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. sakazakii DD13135 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. cloacae DD13151 DuPont Escherichia Neg. Neg. Neg. Neg. Neg. Neg. hermanii DD13162 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. hormaechei DD13163 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. turicensis DD13161 DuPont Enterobacter Neg. Neg. Neg. Neg. Neg. Neg. asburiae DD1535 DuPont Salmonella Neg. Neg. Neg. Neg. Neg. Neg. DD1774 DuPont Salmonella Neg. Neg. Neg. Neg. Neg. Neg. diarazoniae

TABLE 7 E. coli exclusivity BAX ® System Results stx₁ Sample O and/or ID Location type O45 O103 O145 stx₂ eae O157:H7 R61 MSU O45 Pos. Neg. Neg. nt nt nt R65 MSU O103 Neg. Pos. Neg. nt nt nt R77 MSU O145 Neg. Neg. Pos. nt nt nt DD640 DuPont O157 Neg. Neg. Neg. nt nt nt DD641 DuPont O157 Neg. Neg. Neg. nt nt nt DD1718 DuPont O128 Neg. Neg. Neg. Neg. Pos. Neg. DD1721 DuPont O114 Neg. Neg. Neg. Neg. Neg. Neg. DD1730 DuPont O86 Neg. Neg. Neg. Neg. Neg. Neg. DD1732 DuPont O143 Neg. Neg. Neg. Neg. Neg. Neg. DD1762 DuPont O164 Neg. Neg. Neg. Neg. Neg. Neg. DD1769 DuPont O139 Neg. Neg. Neg. Pos. Neg. Neg. DD1770 DuPont O115 Neg. Neg. Neg. Neg. Neg. Neg. DD1803 DuPont O25 Neg. Neg. Neg. Neg. Neg. Neg. DD1814 DuPont O6 Neg. Neg. Neg. Pos. Neg. Neg. DD1821 DuPont O55 Neg. Neg. Neg. Neg. Neg. Neg. DD1827 DuPont O20 Neg. Neg. Neg. Neg. Neg. Neg. DD1835 DuPont O127 Neg. Neg. Neg. Neg. Neg. Neg. DD1836 DuPont O125 Neg. Neg. Neg. Neg. Neg. Neg. DD1842 DuPont O78 Neg. Neg. Neg. Neg. Neg. Neg. DD1861 DuPont O126 Neg. Neg. Neg. Neg. Neg. Neg. DD1889 DuPont O152 Neg. Neg. Neg. Neg. Neg. Neg. DD1915 DuPont O28 Neg. Neg. Neg. Neg. Neg. Neg. DD2432 DuPont O165 Neg. Neg. Neg. Neg. Neg. Neg. DD2434 DuPont O1 Neg. Neg. Neg. Neg. Neg. Neg. DD2438 DuPont O118 Neg. Neg. Neg. Neg. Neg. Neg. DD2441 DuPont O117 Neg. Neg. Neg. Neg. Neg. Neg. DD2445 USDA O113 Neg. Neg. Neg. Neg. Neg. Neg. DD2480 USDA O4 Neg. Neg. Neg. Neg. Neg. Neg. DD3124 USDA O2 Neg. Neg. Neg. Neg. Neg. Neg. DD3130 USDA O8 Neg. Neg. Neg. Neg. Neg. Neg. DD5884 USDA O91 Neg. Neg. Neg. Pos. Neg. Neg. DD13415 USDA O165 Neg. Neg. Neg. Pos. Pos. Neg. DD13417 USDA O4 Neg. Neg. Neg. Pos. Pos. Neg. DD13418 USDA O14 Neg. Neg. Neg. Pos. Pos. Neg. DD13419 USDA O22 Neg. Neg. Neg. Pos. Neg. Neg. DD13420 USDA O28 Neg. Neg. Neg. Pos. Neg. Neg. DD13421 USDA O38 Neg. Neg. Neg. Pos. Neg. Neg. DD13422 USDA O48 Neg. Neg. Neg. Pos. Neg. Neg. DD13423 USDA O79 Neg. Neg. Neg. Pos. Neg. Neg. DD13424 USDA O83 Neg. Neg. Neg. Pos. Pos. Neg. DD13425 USDA O88 Neg. Neg. Neg. Pos. Neg. Neg. DD13426 USDA O93 Neg. Neg. Neg. Pos. Neg. Neg. DD13427 USDA O104 Neg. Neg. Neg. Pos. Neg. Neg. DD13428 USDA O117 Neg. Neg. Neg. Pos. Neg. Neg. DD13429 USDA O119 Neg. Neg. Neg. Pos. Neg. Neg. DD13430 USDA O125 Neg. Neg. Neg. Pos. Pos. Neg. DD13431 USDA O126 Neg. Neg. Neg. Pos. Neg. Neg. DD13432 USDA O128 Neg. Neg. Neg. Pos. Neg. Neg. DD13433 USDA O137 Neg. Neg. Neg. Pos. Neg. Neg. DD13434 USDA O146 Neg. Neg. Neg. Pos. Neg. Neg. DD13435 USDA O165 Neg. Neg. Neg. Pos. Pos. Neg. DD13436 USDA OX3 Neg. Neg. Neg. Pos. Neg. Neg. DD13437 USDA O113 Neg. Neg. Neg. Pos. Neg. Neg. DD13438 USDA O165 Neg. Neg. Neg. Pos. Pos. Neg. DD13439 USDA O5 Neg. Neg. Neg. Pos. Pos. Neg. DD13440 USDA O55 Neg. Neg. Neg. Pos. Pos. Neg. DD13441 USDA O91 Neg. Neg. Neg. Pos. Neg. Neg. DD13442 USDA O2 Neg. Neg. Neg. Pos. Neg. Neg. DD13443 USDA O2 Neg. Neg. Neg. Pos. Neg. Neg. DD13444 USDA O2 Neg. Neg. Neg. Pos. Neg. Neg. DD13445 USDA O128 Neg. Neg. Neg. Pos. Neg. Neg. DD13446 USDA O128 Neg. Neg. Neg. Pos. Neg. Neg. DD13447 USDA O63 Neg. Neg. Neg. Neg. Pos. Neg. DD13448 USDA O63 Neg. Neg. Neg. Pos. Pos. Neg. DD13449 USDA O63 Neg. Neg. Neg. Pos. Neg. Neg. DD13450 USDA O113 Neg. Neg. Neg. Pos. Neg. Neg. DD13451 USDA O113 Neg. Neg. Neg. Pos. Neg. Neg. DD13452 USDA O113 Neg. Neg. Neg. Pos. Neg. Neg. DD13453 USDA O91 Neg. Neg. Neg. Pos. Neg. Neg. DD13454 USDA O91 Neg. Neg. Neg. Pos. Neg. Neg. DD13455 USDA O2 Neg. Neg. Neg. Neg. Pos. Neg. DD13456 USDA O2 Neg. Neg. Neg. Pos. Pos. Neg. DD13457 USDA O2 Neg. Neg. Neg. Pos. Neg. Neg. DD13458 USDA O174 Neg. Neg. Neg. Pos. Neg. Neg. DD13459 USDA O55 Neg. Neg. Neg. Pos. Pos. Neg. DD13460 USDA O128 Neg. Neg. Neg. Neg. Pos. Neg. DD13461 USDA O177 Neg. Neg. Neg. Pos. Pos. Neg. DD13462 USDA O111 Neg. Neg. Neg. Pos. Pos. Neg. DD13463 USDA O113 Neg. Neg. Neg. Pos. Neg. Neg. DD13464 USDA O103 Neg. Pos. Neg. Pos. Pos. Neg. DD13465 USDA O26 Neg. Neg. Neg. Pos. Pos. Neg. DD13466 USDA O41 Neg. Neg. Neg. Pos. Pos. Neg. nt = not tested

Example 2 Determination of Inclusivity/Exclusivity of the O26, O111, and O121 Primers and Probes

As O26, O111, and O121 are additional strains of STEC bacteria, samples of organisms were analyzed to establish inclusivity and exclusivity of a multiplex of O26, O111, and O121 Scorpion® probes of the present invention. For inclusivity, independent, bona fide E. coli O26, O111, and O121 isolates were used. For exclusivity, non-E. coli species and E. coli that did not belong to any of these three serotypes were used to ensure that the assay would discriminate the target organisms (O26, O111, and O121) from other bacteria.

DNA Lysate Preparation

DNA lysates were prepare using the methodology described in Example 1

PCR Conditions

30 μl of the DNA lysate was used to hydrate lyophilized PCR reaction components to achieve a DNA lysate/PCR reaction component mixture as described in Example 1. The primers and probes listed in Table 8 were included in the amounts provided. For the Scorpion® probes, the 5′ end label, internal label, and linker are also provided in Table 8. Each of these Scorpion® probes was designed as a unimolecular Scorpion®, such that its structure includes (in 5′ to 3′ order) a 5′ fluorescent end label, a 5′ stem sequence, a probe sequence, a 3′ stem sequence, an internal quencher, an 18-carbon non-amplifiable linker, and a primer sequence, wherein the 5′ and 3′ stem sequences are reverse complements of one another such that they form a stem-loop structure that results in quenching of the 5′ end label when the probe is not bound to its target.

TABLE 8 Nucleic acid primers, probes, and quenchers used for inclusivity and exclusivity testing For Scorpions Probe SEQ SEQ Internal Primer Amt. Per ID End ID Label/ SEQ Nucleotide Name Target reaction NO: Label NO: Linker ID NO: Scorpion O26  0.75 Cal 228 BHQ2/ 213 (Unimolecular) pMole Fluor 18- O26A-944 UM02 Red Carbon 610 Linker Forward Primer O26  5.25 213 O26A944-29 pMole Reverse Primer O26  6.0 265 O26Arc1070-28 pMole Scorpion O111 1.5 Cal 297 BHQ1/ 282 (Unimolecular) pMole Fluor 18- O111-rc320 UM02 Gold Carbon 540 Linker Forward Primer O111 4.5 282 O111Arc320-29 pMole Reverse Primer O111 6.0 334 O111A158-22 pMole Scorpion O121 1.5 Quasar 364 BHQ2/ 349 (Unimolecular) pMole 670 18- O121A-rc214B UM01 Carbon Linker Forward Primer O121 4.5 349 O121A-rc214-22 pMole Reverse Primer O121 6.0 400 O121A90-27 pMole Scorpion Pos. 1.05 Tamra 697 BHQ2/ 699 (Unimolecular) Control pMole 18- SV40 scorpion 1 Carbon Linker Forward Primer Pos. 2.25 698 SV4312 Control pMole Reverse Primer Pos. 4.5 700 SV4222 Control pMole

Amplification and testing were performed on the BAX® Q7 machine (DuPont Qualicon, Wilmington, Del.). The thermal cycling conditions were as follows: 2 minutes at 94° C., followed by 40 cycles of 94° C. for 10 seconds and 63° C. for 40 seconds, with the fluorescent signal captured during the 63° C. step at each cycle.

Results

As is shown in Tables 9-11, using a multiplex of Scorpion® probes, the method of the present invention was able to discriminate O26, O111, and O121 serotypes from non-target strains, including other O-type E. coli strains and non-E. coli strains (blank results indicate a negative result).

TABLE 9 O26, O111, and O121 inclusivity BAX result Sample ID Location O type O26 O111 O121 R58 MSU O26 Pos. R59 MSU O26 Pos. R60 MSU O26 Pos. R70 MSU O111 Pos. R71 MSU O111 Pos. R72 MSU O111 Pos. R75 MSU O121 Pos. R76 MSU O121 Pos. R84 MDP O121 Pos. R144 MARC O26 Pos. R184 MARC O121 Pos. R185 MARC O121 Pos. R186 MARC O121 Pos. R187 MARC O121 Pos. R188 MARC O121 Pos. DD1720 DD collection O26 Pos. DD1729 DD collection O111 Pos. DD1807 DD collection O26 Pos. DD1808 DD collection O111 Pos. DD1809 DD collection O111 Pos. DD1831 DD collection O26 Pos. DD1858 DD collection O111 Pos. DD1913 DD collection O26 Pos. DD1927 DD collection O111 Pos. DD2440 DD collection O121 Pos. DD2460 DD collection O121 Pos. DD5902 DD collection O26 Pos. DD5903 DD collection O26 Pos. DD5904 DD collection O26 Pos. DD5905 DD collection O26 Pos. DD9704 DD collection O26 Pos. DD9705 DD collection O26 Pos. DD9706 DD collection O26 Pos. DD9707 DD collection O26 Pos. DD13362 USDA O121 Pos. DD13363 USDA O121 Pos. DD13364 USDA O121 Pos. DD13365 USDA O121 Pos. DD13366 USDA O121 Pos. DD13367 USDA O121 Pos. DD13368 USDA O121 Pos. DD13370 USDA O121 Pos. DD133400 USDA O111 Pos. Pos. DD133401 USDA O111 Pos. DD133402 USDA O111 Pos. DD133403 USDA O111 Pos.

TABLE 10 Exclusivity to non-E. coli species BAX result Sample ID Location Species O26 O111 O121 DD373 DD collection Klebsiella pneumoniae Negative Negative Negative DD374 DD collection Proteus mirabilis Negative Negative Negative DD383 DD collection Citrobacter freundii Negative Negative Negative DD657 DD collection Klebsiella ozaenae Negative Negative Negative DD658 DD collection Klebsiella oxytoca Negative Negative Negative DD2389 DD collection Hafnia alvei Negative Negative Negative DD2417 DD collection Serratia liquefaciens Negative Negative Negative DD2558 DD collection Citrobacter freundii Negative Negative Negative DD3064 DD collection Morganella morganii Negative Negative Negative DD3982 DD collection Pseudomonas Negative Negative Negative aeruginosa DD5588 DD collection Hafnia alvei Negative Negative Negative DD6121 DD collection Gram negative rod Negative Negative Negative DD13142 DD collection Morganella morganii Negative Negative Negative DD13147 DD collection Providencia rettgeri Negative Negative Negative DD13148 DD collection Pseudomonas Negative Negative Negative aeruginosa DD13186 DD collection Enterobacter Negative Negative Negative amnigenus DD13187 DD collection Enterobacter Negative Negative Negative amnigenus DD13094 DD collection Enterobacter sakazakii Negative Negative Negative DD13099 DD collection Enterobacter sakazakii Negative Negative Negative DD13134 DD collection Enterobacter sakazakii Negative Negative Negative DD13135 DD collection Enterobacter cloacae Negative Negative Negative DD13151 DD collection Escherichia hermanii Negative Negative Negative DD13162 DD collection Enterobacter Negative Negative Negative hormaechei DD13163 DD collection Enterobacter turicensis Negative Negative Negative DD13161 DD collection Enterobacter asburiae Negative Negative Negative DD1535 DD collection Salmonella Negative Negative Negative DD1774 DD collection Salmonella diarazoniae Negative Negative Negative

TABLE 11 Exclusivity versus other E. coli o-types BAX result Sample ID Location O type O26 O111 O121 R61 MSU O45 Negative Negative Negative R65 MSU O103 Negative Negative Negative R77 MSU O145 Negative Negative Negative DD640 DD collection O157 Negative Negative Negative DD641 DD collection O157 Negative Negative Negative DD1718 DD collection O128 Negative Negative Negative DD1721 DD collection O114 Negative Negative Negative DD1730 DD collection O86 Negative Negative Negative DD1732 DD collection O143 Negative Negative Negative DD1762 DD collection O164 Negative Negative Negative DD1769 DD collection O139 Negative Negative Negative DD1770 DD collection O115 Negative Negative Negative DD1803 DD collection O25 Negative Negative Negative DD1814 DD collection O6 Negative Negative Negative DD1821 DD collection O55 Negative Negative Negative DD1827 DD collection O20 Negative Negative Negative DD1835 DD collection O127 Negative Negative Negative DD1836 DD collection O125 Negative Negative Negative DD1842 DD collection O78 Negative Negative Negative DD1861 DD collection O126 Negative Negative Negative DD1889 DD collection O152 Negative Negative Negative DD1915 DD collection O28 Negative Negative Negative DD2432 DD collection O165 Negative Negative Negative DD2434 DD collection O1 Negative Negative Negative DD2438 DD collection O118 Negative Negative Negative DD2441 DD collection O117 Negative Negative Negative DD2445 USDA O113 Negative Negative Negative DD2480 USDA O4 Negative Negative Negative DD3124 USDA O2 Negative Negative Negative DD3130 USDA O8 Negative Negative Negative DD5884 USDA O91 Negative Negative Negative DD13415 USDA O165 Negative Negative Negative DD13417 USDA O4 Negative Negative Negative DD13418 USDA O14 Negative Negative Negative DD13419 USDA O22 Negative Negative Negative DD13420 USDA O28 Negative Negative Negative DD13421 USDA O38 Negative Negative Negative DD13422 USDA O48 Negative Negative Negative DD13423 USDA O79 Negative Negative Negative DD13424 USDA O83 Positive Negative Negative DD13425 USDA O88 Negative Negative Negative DD13426 USDA O93 Negative Negative Negative DD13427 USDA O104 Negative Negative Negative DD13428 USDA O117 Negative Negative Negative DD13429 USDA O119 Negative Negative Negative DD13430 USDA O125 Negative Negative Negative DD13431 USDA O126 Negative Negative Negative DD13432 USDA O128 Negative Negative Negative DD13433 USDA O137 Negative Negative Negative DD13434 USDA O146 Negative Negative Negative DD13435 USDA O165 Negative Negative Negative DD13436 USDA OX3 Negative Negative Negative DD13437 USDA O113 Negative Negative Negative DD13438 USDA O165 Negative Negative Negative DD13439 USDA O5 Negative Negative Negative DD13440 USDA O55 Negative Negative Negative DD13441 USDA O91 Negative Negative Negative DD13442 USDA O2 Negative Negative Negative DD13443 USDA O2 Negative Negative Negative DD13444 USDA O2 Negative Negative Negative DD13445 USDA O128 Negative Negative Negative DD13446 USDA O128 Negative Negative Negative DD13447 USDA O63 Negative Negative Negative DD13448 USDA O63 Negative Negative Negative DD13449 USDA O63 Negative Negative Negative DD13450 USDA O113 Negative Negative Negative DD13451 USDA O113 Negative Negative Negative DD13452 USDA O113 Negative Negative Negative DD13453 USDA O91 Negative Negative Negative DD13454 USDA O91 Negative Negative Negative DD13455 USDA O2 Negative Negative Negative DD13456 USDA O2 Negative Negative Negative DD13457 USDA O2 Negative Negative Negative DD13458 USDA O174 Negative Negative Negative DD13459 USDA O55 Negative Negative Negative DD13460 USDA O128 Negative Negative Negative DD13461 USDA O177 Negative Negative Negative DD13462 USDA O111 Negative Positive Negative DD13463 USDA O113 Negative Negative Negative DD13464 USDA O103 Negative Negative Negative DD13465 USDA O26 Positive Negative Negative DD13466 USDA O41 Negative Negative Negative 

What is claimed is:
 1. An isolated polynucleotide comprising a primer-probe complex, wherein said primer probe complex comprises: (A) a primer region comprising a nucleic acid sequence comprising at least 15 contiguous nucleotides of SEQ ID NO: 1 and a probe region comprising at least 15 contiguous nucleotides of SEQ ID NO: 16; (B) a primer region comprising SEQ ID NO: 48 and a probe region comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 49-52; (C) a primer region comprising SEQ ID NO: 55, and a probe region comprising SEQ ID NO: 56; (D) a primer region comprising at least 15 contiguous nucleotides of SEQ ID NO: 74 and a probe region comprising at least 15 contiguous nucleotides of SEQ ID NO: 89; (E) a primer region comprising SEQ ID NO: 120 and a probe region comprising a nucleic acid sequence selected from the group consisting of SEQ ID NOs: 121-122; (F) a primer region comprising SEQ ID NO: 125 and a probe region comprising SEQ ID NO: 126; or (G) a primer region comprising at least 15 contiguous nucleotides of SEQ ID NO: 145 and a probe region comprising at least 15 contiguous nucleotides of SEQ ID NO: 160; wherein said probe region and said primer region each have a 5′ and 3′ terminus, wherein said 3′ terminus of said probe region is attached to said 5′ terminus of said primer region via a linker moiety, and wherein said primer-probe complex further comprises a detectable label.
 2. A kit for detection of STEC bacteria in a sample, comprising an isolated polynucleotide of claim
 1. 3. A reagent tablet comprising an isolated polynucleotide of claim
 1. 